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  1. Home
  2. Math Calculators
  3. Sine Calculator

Sine Calculator

Calculate sin(x) for any angle or find the angle from a sine value using arcsin. Features unit circle and sine wave visualizations.

Formula:sin(x) = opposite / hypotenuse

Result

sin(30)

0.500000

Exact: 1/2

Quadrant1 (sin +)
Reference Angle30.00
Equivalent Angles30.0, 150.0

Calculation Mode

Input

Enter angle in degrees

Unit Circle Visualization

xy09018027030(0.866, 0.500)cos = 0.8660sin = 0.5000IIIIIIIV

On the unit circle, sin(30.0) is the y-coordinate of the point: 0.500000

Related Trigonometric Values

sin(30)

0.500000

cos(30)

0.866025

tan(30)

0.577350

csc(30) = 1/sin

2.000000

Cofunction Identity: sin(30) = cos(60)

Sine Wave Graph

Amplitude

1

Period

2pi

Phase Shift

0

Vertical Shift

0

Equation:

y = sin((x))

Special Sine Values

Angle (deg)RadianssinExact Value
000.00000
30pi/60.50001/2
45pi/40.7071sqrt(2)/2
60pi/30.8660sqrt(3)/2
90pi/21.00001
1202pi/30.8660sqrt(3)/2
1353pi/40.7071sqrt(2)/2
1505pi/60.50001/2
180pi0.00000

Sine Function Properties

Domain

All real numbers (-inf, inf)

Range

[-1, 1]

Period

360 degrees (2pi radians)

Odd/Even

Odd function: sin(-x) = -sin(x)

Zeros

x = n*180 (n*pi), where n is integer

Maximum/Minimum

Max = 1 at 90, Min = -1 at 270

Applications of Sine

Sound Waves

Pure tones are modeled by sine waves. The frequency determines pitch, amplitude determines volume.

Harmonic Motion

Pendulums, springs, and oscillations follow sinusoidal patterns: x(t) = A*sin(omega*t + phi)

AC Electricity

Alternating current is sinusoidal: V(t) = V_max * sin(2*pi*f*t)

Navigation

Law of Sines (a/sin(A) = b/sin(B) = c/sin(C)) is used in triangulation and surveying.

Result

sin(30)

0.500000

Try These Examples

Quick-start with common scenarios

Practice Problems

Test your skills with practice problems

Practice with 3 problems to test your understanding.

?What is Sine?

Sine (sin) is a trigonometric function that gives the ratio of the opposite side to the hypotenuse in a right triangle: sin(angle) = opposite/hypotenuse. On the unit circle, sine equals the y-coordinate. Common values: sin(0)=0, sin(30)=0.5, sin(45)=sqrt(2)/2, sin(60)=sqrt(3)/2, sin(90)=1. The inverse sine (arcsin) finds the angle from a sine value.

About the Sine Function

The sine function is one of the fundamental trigonometric functions. For an angle in a right triangle, sine equals the length of the opposite side divided by the hypotenuse. In the unit circle, sine represents the y-coordinate of a point on the circle. Sine oscillates between -1 and 1 and is used extensively in physics for modeling waves, oscillations, and periodic phenomena.

Key Facts

  • sin(x) = opposite / hypotenuse in a right triangle
  • On the unit circle, sin(x) = y-coordinate of the point
  • Range: sine values are always between -1 and 1
  • Period: sine repeats every 360 degrees (2pi radians)
  • sin(0) = 0, sin(90) = 1, sin(180) = 0, sin(270) = -1
  • arcsin(x) returns angle in range [-90, 90] or [-pi/2, pi/2]
  • Sine is positive in quadrants I and II (0-180 degrees)
  • sin(x) = cos(90 - x) - coffunction identity

Frequently Asked Questions

Sine is a trigonometric function that, for an angle in a right triangle, equals the ratio of the opposite side to the hypotenuse. On the unit circle, sin(angle) equals the y-coordinate of the point at that angle. Sine oscillates between -1 and 1.

sin(angle) = opposite/hypotenuse, or the y-coordinate on the unit circle.

sin(30) = 0.5 or 1/2. This is one of the special angles. The exact value comes from the 30-60-90 triangle where the side opposite to 30 is half the hypotenuse.

sin(30) = 0.5 = 1/2. A special angle value to memorize.

Arcsin (also written as sin inverse or asin) returns the angle whose sine equals a given value. For example, arcsin(0.5) = 30 because sin(30) = 0.5. The result is always between -90 and 90 degrees.

arcsin(x) gives the angle whose sine is x. Range: -90 to 90 degrees.

Sine is positive in quadrants I and II (0 to 180 degrees) where the y-coordinate is positive. Sine is negative in quadrants III and IV (180 to 360 degrees) where the y-coordinate is negative.

Positive in Q1 and Q2 (0-180), negative in Q3 and Q4 (180-360).

The sine function has a period of 360 degrees (or 2pi radians). This means sin(x) = sin(x + 360) for any angle x. The function completes one full oscillation every 360 degrees.

Period = 360 (2pi radians). sin(x) = sin(x + 360).

Last updated: 2025-01-15

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Result

sin(30)

0.500000

Exact: 1/2

Quadrant1 (sin +)
Reference Angle30.00
Equivalent Angles30.0, 150.0