Sin Inverse

Free online arcsin calculator: compute inverse sine of any value between -1 and 1. Get the angle instantly in degrees and radians with an interactive function graph.

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About This Calculator

The inverse sine function, denoted sin⁻¹(x) or arcsin(x), returns the angle whose sine equals the input value x. It is the inverse operation of the sine function. The result is an angle typically measured in degrees or radians, with the principal value lying between -90 deg and 90 deg (-pi/2 to pi/2 radians). This free sin inverse calculator provides both degree and radian outputs simultaneously, along with an interactive arcsin graph for visual reference.

The mathematical formula for arcsin is: theta = arcsin(x) where sin(theta) = x and x must be in the domain [-1, 1]. This calculator computes both degree and radian outputs simultaneously, making it useful for students, engineers, and professionals who need quick trigonometric inverse calculations. Simply enter any value between -1 and 1, and the calculator instantly returns the corresponding angle using the JavaScript Math.asin() function which implements the IEEE 754 standard for inverse sine computation.

Inverse sine is fundamental in trigonometry, physics (calculating refraction angles using Snell's law), engineering (determining structural angles in truss analysis), computer graphics (computing rotation matrices for 3D rendering), and navigation (calculating bearing corrections). Understanding arcsin is essential for solving right triangles, analyzing periodic phenomena, and working with inverse trigonometric identities. The function is also closely related to arccosine through the identity arcsin(x) + arccos(x) = pi/2.

For students studying calculus, the derivative of arcsin(x) is 1/sqrt(1-x^2) and its integral is x·arcsin(x) + sqrt(1-x^2) + C. Common arcsin values to remember include arcsin(0) = 0 deg, arcsin(1/2) = 30 deg, arcsin(sqrt2/2) = 45 deg, arcsin(sqrt3/2) = 60 deg, and arcsin(1) = 90 deg. The graph of arcsin(x) is the reflection of the sine function's principal branch across the line y = x, creating a characteristic S-shaped curve that increases monotonically from (-1, -90 deg) to (1, 90 deg).

Frequently Asked Questions

What is sin⁻¹ or inverse sine?

Sin inverse (arcsin) is the inverse function of sine. If sin(theta) = x, then arcsin(x) = theta. It returns the angle whose sine equals the given number. The output range is -90 deg to 90 deg (-pi/2 to pi/2 radians).

What values can I input for sin inverse?

The inverse sine function only accepts values between -1 and 1 (inclusive), since the sine of any angle always falls within this range. Inputs outside this range will not produce a valid real result.

How do you calculate arcsin manually?

Arcsin can be calculated using the series expansion: arcsin(x) = x + (1/6)x^3 + (3/40)x^5 + ... for |x| < 1. For x = 0.5, arcsin(0.5) = 30 deg (pi/6 rad). Most calculators use the CORDIC algorithm or Taylor series internally.

What is the difference between sin⁻¹ and arcsin?

Sin inverse (sin⁻¹), arcsin, and asin all refer to the same mathematical function: the inverse of the sine function. Different calculators and textbooks may use different notation, but they all compute the same value.

Where is inverse sine used in real life?

Inverse sine is widely used in physics for calculating angles from trigonometric ratios, in engineering for structural analysis, in navigation for course correction, in computer graphics for 3D rotations, and in signal processing for phase angle calculation.

What is the derivative of arcsin?

The derivative of arcsin(x) is 1 / sqrt(1 - x^2) for |x| < 1. This formula is derived from implicit differentiation of sin(y) = x and is useful in calculus for integrating expressions involving square roots.

How do you use arcsin in programming?

In most programming languages, arcsin is available as Math.asin() (JavaScript), math.asin() (Python), or asin() (C/Java). The result is always in radians, so convert to degrees by multiplying by 180/pi if needed.

Is this sin inverse calculator free?

Yes, all calculators on Calculy are completely free to use. No registration or download required.