جيب (رياضيات)

جيب Sine في الرياضيات هو النسبة بين الضلع المقابل لزاوية والوتر في مثلث ذو زاوية قائمة ، بحيث يكون الوتر هو الضلع المقابل للزاوية القائمة.

Sine
ملف:Sine one period.svg
Basic features
Parity	odd
Domain	(−∞,∞) a
Codomain	[−1,1] a
Period	2π
Specific values
At zero	0
Maxima	((2k + ½)π, 1) b
Minima	((2k − ½)π, −1)
Specific features
Root	kπ
Critical point	kπ − π/2
Inflection point	kπ
Fixed point	0
a  For real numbers. b  Variable k is an integer.

في رياضيات، تعتبر التوابع مثلثية أو الدوال المثلثية دوال لزاوية هندسية، و هي دوال مهمة عندما نريد دراسة مثلث أوعرض ظواهرِ دورية. يمكن تعريف هذه الدوال كنسبة لأضلاع مثلث قائم الذي يَحتوي تلك الزاويةَ أَو بشكل أكثر عمومية كإحداثيات على دائرة مثلثية أو دائرة واحدية (unit circle) . في الرياضيات ، الدوال المثلثية هي دوال ترتبط بالزاوية، وهي مهمة في دراسة المثلثات وتمثيل الظواهر المتكررة (كالموجات). ويمكن تعريف الدوال المثلثية على أنهم نسب بين ضلعين في مثلث قائم فيه الزاوية المعنية، او ، وبشكل أوسع. كنسبة بين إحداثيات نقاط على دائرة الوحدة، ويعتبر دوما عند الإشارة إلى المثلثات ان الحديث يدور حول مثلث في سطح مستوي (مستوى إحداثي أو إقليدي) ، وذلك ليكون مجموع الزوايا 180 درجة دائما.

دالة جيب التمام.

وهناك ثلاثة دوال مثلثية أساسية هي:

• جا أو الجيب ، ويساوي النسبة بين الضلع المقابل للزاوية مقسوما على الوتر.
• جتا أو جيب التمام ، ويساوي النسبة بين الضلع المجاور للزاوية مقسوما على الوتر.
• ظا او الظل ، ويساوي النسبية بين الضلع المقابل للزاوية والضلع المجاور لها.

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 Identities

المقالة الرئيسية: List of trigonometric identities

Exact identities (using radians):

These apply for all values of $\theta$.

$\sin(\theta )=\cos \left({\frac {\pi }{2}}-\theta \right)={\frac {1}{\csc(\theta )}}$

 Reciprocal

The reciprocal of sine is cosecant, i.e., the reciprocal of sin(A) is csc(A), or cosec(A). Cosecant gives the ratio of the length of the hypotenuse to the length of the opposite side:

$\csc(A)={\frac {1}{\sin(A)}}={\frac {\textrm {hypotenuse}}{\textrm {opposite}}}={\frac {h}{a}}.$

 Inverse

The usual principal values of the arcsin(x) function graphed on the cartesian plane. Arcsin is the inverse of sin.

 Calculus

انظر أيضاً: List of integrals of trigonometric functions and Differentiation of trigonometric functions

For the sine function:

$f(x)=\sin(x)$

The derivative is:

$f'(x)=\cos(x)$

The antiderivative is:

$\int f(x)\,dx=-\cos x+C$

C denotes the constant of integration.

 Other trigonometric functions

The sine and cosine functions are related in multiple ways. The two functions are out of phase by 90°: $\sin(\pi /2-x)$ = $\cos(x)$ for all angles x. Also, the derivative of the function sin(x) is cos(x).

It is possible to express any trigonometric function in terms of any other (up to a plus or minus sign, or using the sign function).

Sine in terms of the other common trigonometric functions:

	f θ	Using plus/minus (±)					Using sign function (sgn)
		f θ =	± per Quadrant				f θ =
			I	II	III	IV
cos	$\sin(\theta )$	$=\pm {\sqrt {1-\cos ^{2}(\theta )}}$	+	+	−	−	$=\operatorname {sgn} \left(\cos \left(\theta -{\frac {\pi }{2}}\right)\right){\sqrt {1-\cos ^{2}(\theta )}}$
	$\cos(\theta )$	$=\pm {\sqrt {1-\sin ^{2}(\theta )}}$	+	−	−	+	$=\operatorname {sgn} \left(\sin \left(\theta +{\frac {\pi }{2}}\right)\right){\sqrt {1-\sin ^{2}(\theta )}}$
cot	$\sin(\theta )$	$=\pm {\frac {1}{\sqrt {1+\cot ^{2}(\theta )}}}$	+	+	−	−	$=\operatorname {sgn} \left(\cot \left({\frac {\theta }{2}}\right)\right){\frac {1}{\sqrt {1+\cot ^{2}(\theta )}}}$
	$\cot(\theta )$	$=\pm {\frac {\sqrt {1-\sin ^{2}(\theta )}}{\sin(\theta )}}$	+	−	−	+	$=\operatorname {sgn} \left(\sin \left(\theta +{\frac {\pi }{2}}\right)\right){\frac {\sqrt {1-\sin ^{2}(\theta )}}{\sin(\theta )}}$
tan	$\sin(\theta )$	$=\pm {\frac {\tan(\theta )}{\sqrt {1+\tan ^{2}(\theta )}}}$	+	−	−	+	$=\operatorname {sgn} \left(\tan \left({\frac {2\theta +\pi }{4}}\right)\right){\frac {\tan(\theta )}{\sqrt {1+\tan ^{2}(\theta )}}}$
	$\tan(\theta )$	$=\pm {\frac {\sin(\theta )}{\sqrt {1-\sin ^{2}(\theta )}}}$	+	−	−	+	$=\operatorname {sgn} \left(\sin \left(\theta +{\frac {\pi }{2}}\right)\right){\frac {\sin(\theta )}{\sqrt {1-\sin ^{2}(\theta )}}}$
sec	$\sin(\theta )$	$=\pm {\frac {\sqrt {\sec ^{2}(\theta )-1}}{\sec(\theta )}}$	+	−	+	−	$=\operatorname {sgn} \left(\sec \left({\frac {4\theta -\pi }{2}}\right)\right){\frac {\sqrt {\sec ^{2}(\theta )-1}}{\sec(\theta )}}$
	$\sec(\theta )$	$=\pm {\frac {1}{\sqrt {1-\sin ^{2}(\theta )}}}$	+	−	−	+	$=\operatorname {sgn} \left(\sin \left(\theta +{\frac {\pi }{2}}\right)\right){\frac {1}{\sqrt {1-\sin ^{2}(\theta )}}}$

Note that for all equations which use plus/minus (±), the result is positive for angles in the first quadrant.

The basic relationship between the sine and the cosine can also be expressed as the Pythagorean trigonometric identity:

$\cos ^{2}(\theta )+\sin ^{2}(\theta )=1\!$

where sin²x means (sin(x))².

 Properties relating to the quadrants

The four quadrants of a Cartesian coordinate system.

Over the four quadrants of the sine function is as follows.

Quadrant	Degrees	Radians	Value	Sign	Monotony	Convexity
1st Quadrant	$0^{\circ }<x<90^{\circ }$	$0<x<{\frac {\pi }{2}}$	$0<\sin(x)<1$	$+$	increasing	concave
2nd Quadrant	$90^{\circ }<x<180^{\circ }$	${\frac {\pi }{2}}<x<\pi$	$0<\sin(x)<1$	$+$	decreasing	concave
3rd Quadrant	$180^{\circ }<x<270^{\circ }$	$\pi <x<{\frac {3\pi }{2}}$	$-1<\sin(x)<0$	$-$	decreasing	convex
4th Quadrant	$270^{\circ }<x<360^{\circ }$	${\frac {3\pi }{2}}<x<2\pi$	$-1<\sin(x)<0$	$-$	increasing	convex

Points between the quadrants. k is an integer.

The quadrants of the unit circle and of sin x, using the Cartesian coordinate system.

Degrees	Radians $0\leq x<2\pi$	Radians	$\sin(x)$	Point type
$0^{\circ }$	$0$	$2\pi k$	$0$	Root, Inflection
$90^{\circ }$	${\frac {\pi }{2}}$	$2\pi k+{\frac {\pi }{2}}$	$1$	Maximum
$180^{\circ }$	$\pi$	$2\pi k-\pi$	$0$	Root, Inflection
$270^{\circ }$	${\frac {3\pi }{2}}$	$2\pi k-{\frac {\pi }{2}}$	$-1$	Minimum

For arguments outside those in the table, get the value using the fact the sine function has a period of 360° (or 2π rad): $\sin(\alpha +360^{\circ })=\sin(\alpha )$, or use $\sin(\alpha +180^{\circ })=-\sin(\alpha )$. Or use $\cos(x)={\frac {e^{xi}+e^{-xi}}{2}}$ and $\sin(x)={\frac {e^{xi}-e^{-xi}}{2i}}$. For complement of sine, we have $\sin(180^{\circ }-\alpha )=\sin(\alpha )$.

 Series definition

The sine function (blue) is closely approximated by its Taylor polynomial of degree 7 (pink) for a full cycle centered on the origin.

This animation shows how including more and more terms in the partial sum of its Taylor series approaches a sine curve.

Using only geometry and properties of limits, it can be shown that the derivative of sine is cosine, and that the derivative of cosine is the negative of sine.

Using the reflection from the calculated geometric derivation of the sine is with the 4n + k-th derivative at the point 0:

$\sin ^{(4n+k)}(0)={\begin{cases}0&{\text{when }}k=0\\1&{\text{when }}k=1\\0&{\text{when }}k=2\\-1&{\text{when }}k=3\end{cases}}$

This gives the following Taylor series expansion at x = 0. One can then use the theory of Taylor series to show that the following identities hold for all real numbers x (where x is the angle in radians) :

${\begin{aligned}\sin x&=x-{\frac {x^{3}}{3!}}+{\frac {x^{5}}{5!}}-{\frac {x^{7}}{7!}}+\cdots \\[8pt]&=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{(2n+1)!}}x^{2n+1}\\[8pt]\end{aligned}}$

If x were expressed in degrees then the series would contain factors involving powers of π/180: if x is the number of degrees, the number of radians is y = πx /180, so

${\begin{aligned}\sin x_{\mathrm {deg} }&=\sin y_{\mathrm {rad} }\\&={\frac {\pi }{180}}x-\left({\frac {\pi }{180}}\right)^{3}{\frac {x^{3}}{3!}}+\left({\frac {\pi }{180}}\right)^{5}{\frac {x^{5}}{5!}}-\left({\frac {\pi }{180}}\right)^{7}{\frac {x^{7}}{7!}}+\cdots .\end{aligned}}$

The series formulas for the sine and cosine are uniquely determined, up to the choice of unit for angles, by the requirements that

${\begin{aligned}\sin 0=0&{\text{ and }}\sin {2x}=2\sin x\cos x\\\cos ^{2}x+\sin ^{2}x=1&{\text{ and }}\cos {2x}=\cos ^{2}x-\sin ^{2}x\\\end{aligned}}$

The radian is the unit that leads to the expansion with leading coefficient 1 for the sine and is determined by the additional requirement that

$\sin x\approx x{\text{ when }}x\approx 0.$

The coefficients for both the sine and cosine series may therefore be derived by substituting their expansions into the pythagorean and double angle identities, taking the leading coefficient for the sine to be 1, and matching the remaining coefficients.

In general, mathematically important relationships between the sine and cosine functions and the exponential function (see, for example, Euler's formula) are substantially simplified when angles are expressed in radians, rather than in degrees, grads or other units. Therefore, in most branches of mathematics beyond practical geometry, angles are generally assumed to be expressed in radians.

A similar series is Gregory's series for arctan, which is obtained by omitting the factorials in the denominator.

 Continued fraction

The sine function can also be represented as a generalized continued fraction:

$\sin x={\cfrac {x}{1+{\cfrac {x^{2}}{2\cdot 3-x^{2}+{\cfrac {2\cdot 3x^{2}}{4\cdot 5-x^{2}+{\cfrac {4\cdot 5x^{2}}{6\cdot 7-x^{2}+\ddots }}}}}}}}.$

The continued fraction representation can be derived from Euler's continued fraction formula and expresses the real number values, both rational and irrational, of the sine function.

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 Fixed point

The fixed point iteration x_n+1 = sin x_n with initial value x₀ = 2 converges to 0.

Zero is the only real fixed point of the sine function; in other words the only intersection of the sine function and the identity function is sin(0) = 0.

 Arc length

The arc length of the sine curve between $a$ and $b$ is $\int _{a}^{b}\!{\sqrt {1+\cos(x)^{2}}}\,dx$ This integral is an elliptic integral of the second kind.

The arc length for a full period is ${\frac {4\pi ^{3/2}{\sqrt {2}}}{\Gamma (1/4)^{2}}}+{\frac {\Gamma (1/4)^{2}}{\sqrt {2\pi }}}=7.640395578\ldots$ where $\Gamma$ is the Gamma function.

The arc length of the sine curve from 0 to x is the above number divided by $2\pi$ times x, plus a correction that varies periodically in x with period $\pi$. The Fourier series for this correction can be written in closed form using special functions, but it is perhaps more instructive to write the decimal approximations of the Fourier coefficients. The sine curve arc length from 0 to x is

$1.21600672\times x+0.10317093\sin(2x)-0.00220445\sin(4x)+0.00012584\sin(6x)-0.00001011\sin(8x)+\cdots$

 Law of sines

المقالة الرئيسية: Law of sines

The law of sines states that for an arbitrary triangle with sides a, b, and c and angles opposite those sides A, B and C:

${\frac {\sin A}{a}}={\frac {\sin B}{b}}={\frac {\sin C}{c}}.$

This is equivalent to the equality of the first three expressions below:

${\frac {a}{\sin A}}={\frac {b}{\sin B}}={\frac {c}{\sin C}}=2R,$

where R is the triangle's circumradius.

It can be proven by dividing the triangle into two right ones and using the above definition of sine. The law of sines is useful for computing the lengths of the unknown sides in a triangle if two angles and one side are known. This is a common situation occurring in triangulation, a technique to determine unknown distances by measuring two angles and an accessible enclosed distance.

 Special values

انظر أيضاً: Exact trigonometric constants

Some common angles (θ) shown on the unit circle. The angles are given in degrees and radians, together with the corresponding intersection point on the unit circle, (cos θ, sin θ).

For certain integral numbers x of degrees, the value of sin(x) is particularly simple. A table of some of these values is given below.

x (angle)				sin x
Degrees	Radians	Gradians	Turns	Exact	Decimal
0°	0	0g	0	0	0
180°	π	200g	1/2
15°	1/12π	16+2/3g	1/24	${\frac {{\sqrt {6}}-{\sqrt {2}}}{4}}$	0.258819045102521
165°	11/12π	183+1/3g	11/24
30°	1/6π	33+1/3g	1/12	1/2	0.5
150°	5/6π	166+2/3g	5/12
45°	1/4π	50g	1/8	${\frac {\sqrt {2}}{2}}$	0.707106781186548
135°	3/4π	150g	3/8
60°	1/3π	66+2/3g	1/6	${\frac {\sqrt {3}}{2}}$	0.866025403784439
120°	2/3π	133+1/3g	1/3
75°	5/12π	83+1/3g	5/24	${\frac {{\sqrt {6}}+{\sqrt {2}}}{4}}$	0.965925826289068
105°	7/12π	116+2/3g	7/24
90°	1/2π	100g	1/4	1	1

90 degree increments:

x in degrees	0°	90°	180°	270°	360°
x in radians	0	π/2	π	3π/2	2π
x in gons	0	100g	200g	300g	400g
x in turns	0	1/4	1/2	3/4	1
sin x	0	1	0	-1	0

Other values not listed above:

$\sin {\frac {\pi }{60}}=\sin 3^{\circ }={\frac {(2-{\sqrt {12}}){\sqrt {5+{\sqrt {5}}}}+({\sqrt {10}}-{\sqrt {2}})({\sqrt {3}}+1)}{16}}$ OEIS: A019812

$\sin {\frac {\pi }{30}}=\sin 6^{\circ }={\frac {{\sqrt {30-{\sqrt {180}}}}-{\sqrt {5}}-1}{8}}$ OEIS: A019815

$\sin {\frac {\pi }{20}}=\sin 9^{\circ }={\frac {{\sqrt {10}}+{\sqrt {2}}-{\sqrt {20-{\sqrt {80}}}}}{8}}$ OEIS: A019818

$\sin {\frac {\pi }{15}}=\sin 12^{\circ }={\frac {{\sqrt {10+{\sqrt {20}}}}+{\sqrt {3}}-{\sqrt {15}}}{8}}$ OEIS: A019821

$\sin {\frac {\pi }{10}}=\sin 18^{\circ }={\frac {{\sqrt {5}}-1}{4}}={\tfrac {1}{2}}\varphi ^{-1}$ OEIS: A019827

$\sin {\frac {7\pi }{60}}=\sin 21^{\circ }={\frac {(2+{\sqrt {12}}){\sqrt {5-{\sqrt {5}}}}-({\sqrt {10}}+{\sqrt {2}})({\sqrt {3}}-1)}{16}}$ OEIS: A019830

$\sin {\frac {\pi }{8}}=\sin 22.5^{\circ }={\frac {\sqrt {2-{\sqrt {2}}}}{2}}$

$\sin {\frac {2\pi }{15}}=\sin 24^{\circ }={\frac {{\sqrt {3}}+{\sqrt {15}}-{\sqrt {10-{\sqrt {20}}}}}{8}}$ OEIS: A019833

$\sin {\frac {3\pi }{20}}=\sin 27^{\circ }={\frac {{\sqrt {20+{\sqrt {80}}}}-{\sqrt {10}}+{\sqrt {2}}}{8}}$ OEIS: A019836

$\sin {\frac {11\pi }{60}}=\sin 33^{\circ }={\frac {({\sqrt {12}}-2){\sqrt {5+{\sqrt {5}}}}+({\sqrt {10}}-{\sqrt {2}})({\sqrt {3}}+1)}{16}}$ OEIS: A019842

$\sin {\frac {\pi }{5}}=\sin 36^{\circ }={\frac {\sqrt {10-{\sqrt {20}}}}{4}}$ OEIS: A019845

$\sin {\frac {13\pi }{60}}=\sin 39^{\circ }={\frac {(2-{\sqrt {12}}){\sqrt {5-{\sqrt {5}}}}+({\sqrt {10}}+{\sqrt {2}})({\sqrt {3}}+1)}{16}}$ OEIS: A019848

$\sin {\frac {7\pi }{30}}=\sin 42^{\circ }={\frac {{\sqrt {30+{\sqrt {180}}}}-{\sqrt {5}}+1}{8}}$ OEIS: A019851

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 Relationship to complex numbers

المقالة الرئيسية: Trigonometric functions § Relationship to exponential function and complex numbers

An illustration of the complex plane. The imaginary numbers are on the vertical coordinate axis.

Sine is used to determine the imaginary part of a complex number given in polar coordinates (r,φ):

$z=r(\cos \varphi +i\sin \varphi )$

the imaginary part is:

$\operatorname {Im} (z)=r\sin \varphi$

r and φ represent the magnitude and angle of the complex number respectively. i is the imaginary unit. z is a complex number.

Although dealing with complex numbers, sine's parameter in this usage is still a real number. Sine can also take a complex number as an argument.

 Sine with a complex argument

$\sin z$

Domain coloring of sin(z) over (-π,π) on x and y axes. Brightness indicates absolute magnitude, saturation represents complex argument.

sin(z) as a vector field

$\sin(\theta )$ is the imaginary part of $\mathrm {e} ^{\mathrm {i} \theta }$.

The definition of the sine function for complex arguments z:

${\begin{aligned}\sin z&=\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{(2n+1)!}}z^{2n+1}\\&={\frac {e^{iz}-e^{-iz}}{2i}}\\&={\frac {\sinh \left(iz\right)}{i}}\end{aligned}}$

where i ² = −1, and sinh is hyperbolic sine. This is an entire function. Also, for purely real x,

$\sin x=\operatorname {Im} (e^{ix}).$

For purely imaginary numbers:

$\sin iy=i\sinh y.$

It is also sometimes useful to express the complex sine function in terms of the real and imaginary parts of its argument:

${\begin{aligned}\sin(x+iy)&=\sin x\cos iy+\cos x\sin iy\\&=\sin x\cosh y+i\cos x\sinh y.\end{aligned}}$

 Partial fraction and product expansions of complex sine

Using the partial fraction expansion technique in complex analysis, one can find that the infinite series

${\begin{aligned}\sum _{n=-\infty }^{\infty }{\frac {(-1)^{n}}{z-n}}={\frac {1}{z}}-2z\sum _{n=1}^{\infty }{\frac {(-1)^{n}}{n^{2}-z^{2}}}\end{aligned}}$

both converge and are equal to ${\frac {\pi }{\sin \pi z}}$. Similarly, one can show that

${\begin{aligned}{\frac {\pi ^{2}}{\sin ^{2}(\pi z)}}=\sum _{n=-\infty }^{\infty }{\frac {1}{(z-n)^{2}}}.\end{aligned}}$

Using product expansion technique, one can derive

${\begin{aligned}\sin \pi z=\pi z\prod _{n=1}^{\infty }{\Bigl (}1-{\frac {z^{2}}{n^{2}}}{\Bigr )}.\end{aligned}}$

 Usage of complex sine

sin z is found in the functional equation for the Gamma function,

$\Gamma (s)\Gamma (1-s)={\pi \over \sin \pi s},$

which in turn is found in the functional equation for the Riemann zeta-function,

$\zeta (s)=2(2\pi )^{s-1}\Gamma (1-s)\sin(\pi s/2)\zeta (1-s).$

As a holomorphic function, sin z is a 2D solution of Laplace's equation:

$\Delta u(x_{1},x_{2})=0.$

It is also related with level curves of pendulum.

 Complex graphs

Sine function in the complex plane

real component	imaginary component	magnitude

Arcsine function in the complex plane

real component	imaginary component	magnitude

 History

المقالة الرئيسية: History of trigonometric functions

While the early study of trigonometry can be traced to antiquity, the trigonometric functions as they are in use today were developed in the medieval period. The chord function was discovered by Hipparchus of Nicaea (180–125 BCE) and Ptolemy of Roman Egypt (90–165 CE).

The function sine (and cosine) can be traced to the jyā and koṭi-jyā functions used in Gupta period (320 to 550 CE) Indian astronomy (Aryabhatiya, Surya Siddhanta), via translation from Sanskrit to Arabic and then from Arabic to Latin.

The first published use of the abbreviations 'sin', 'cos', and 'tan' is by the 16th century French mathematician Albert Girard; these were further promulgated by Euler (see below). The Opus palatinum de triangulis of Georg Joachim Rheticus, a student of Copernicus, was probably the first in Europe to define trigonometric functions directly in terms of right triangles instead of circles, with tables for all six trigonometric functions; this work was finished by Rheticus' student Valentin Otho in 1596.

In a paper published in 1682, Leibniz proved that sin x is not an algebraic function of x. Roger Cotes computed the derivative of sine in his Harmonia Mensurarum (1722). Leonhard Euler's Introductio in analysin infinitorum (1748) was mostly responsible for establishing the analytic treatment of trigonometric functions in Europe, also defining them as infinite series and presenting "Euler's formula", as well as the near-modern abbreviations sin., cos., tang., cot., sec., and cosec.

 Etymology

ابحث عن sine في
قاموس المعرفة.

Etymologically, the word sine derives from the Sanskrit word for chord, jiva*(jya being its more popular synonym). This was transliterated in Arabic as jiba جــيــب, which however is meaningless in that language and abbreviated jb جــــب . Since Arabic is written without short vowels, "jb" was interpreted as the word jaib جــيــب, which means "bosom". When the Arabic texts were translated in the 12th century into Latin by Gerard of Cremona, he used the Latin equivalent for "bosom", sinus (which means "bosom" or "bay" or "fold"). Gerard was probably not the first scholar to use this translation, Robert of Chester appears to have preceded him and there is evidence of even earlier usage. The English form sine was introduced in the 1590s.

 Software implementations

انظر أيضاً: Lookup table § Computing sines

The sine function, along with other trigonometric functions, is widely available across programming languages and platforms. In computing, it is typically abbreviated to sin.

Some CPU architectures have a built-in instruction for sine, including the Intel x87 FPUs since the 80387.

In programming languages, sin is typically either a built-in function or found within the language's standard math library.

For example, the C standard library defines sine functions within math.h: sin(double), sinf(float), and sinl(long double). The parameter of each is a floating point value, specifying the angle in radians. Each function returns the same data type as it accepts. Many other trigonometric functions are also defined in math.h, such as for cosine, arc sine, and hyperbolic sine (sinh).

Similarly, Python defines math.sin(x) within the built-in math module. Complex sine functions are also available within the cmath module, e.g. cmath.sin(z). CPython's math functions call the C math library, and use a double-precision floating-point format.

There is no standard algorithm for calculating sine. IEEE 754-2008, the most widely used standard for floating-point computation, does not address calculating trigonometric functions such as sine. Algorithms for calculating sine may be balanced for such constraints as speed, accuracy, portability, or range of input values accepted. This can lead to different results for different algorithms, especially for special circumstances such as very large inputs, e.g. sin(1022 ).

A once common programming optimization, used especially in 3D graphics, was to pre-calculate a table of sine values, for example one value per degree. This allowed results to be looked up from a table rather than being calculated in real time. With modern CPU architectures this method may offer no advantage.

The CORDIC algorithm is commonly used in scientific calculators.

 انظر أيضاً

• Āryabhaṭa's sine table
• Bhaskara I's sine approximation formula
• Discrete sine transform
• Euler's formula
• Generalized trigonometry
• Hyperbolic function
• Law of sines
• List of periodic functions
• List of trigonometric identities
• Madhava series
• Madhava's sine table
• Optical sine theorem
• Polar sine — a generalization to vertex angles
• Proofs of trigonometric identities
• Sinc function
• Sine and cosine transforms
• Sine integral
• Sine quadrant
• Sine wave
• Sine–Gordon equation
• Sinusoidal model
• Trigonometric functions

 References

• Traupman, John C. (1966), The New College Latin & English Dictionary, Toronto: Bantam, ISBN 0-553-27619-0 
• Webster's Seventh New Collegiate Dictionary, Springfield: G. & C. Merriam Company, 1969 

 External links

• Media related to Sine function at Wikimedia Commons