# Inverse Sine Function (Arcsine)

**Arcsine**or on a calculator it will appear as

**asin**or

**sin**. Note: this does NOT mean sine raised to the negative one power.

^{-1}*Let's look at an example of how to use the inverse sine function to find the measure of an angle in a right triangle. (triangle not drawn to scale)*

To find the measure in degrees of angle A using the sine inverse, recall that

Use a scientific calculator *Make sure your calculator is in degree mode

*Let's look at an application problem.*

An airplane is 6000 feet above ground. It is 10,000 feet from the runway. At what angle must the plane descend to land on the target runway?

Begin by creating a sketch that will organize the data and show a right triangle.

*Alternate interior angles are congruent

Use a scientific calculator *Make sure your calculator is in degree mode

If it is understood how to use the basic right triangle trigonometric ratios, then the inverse can be used to find a missing angle measure in any right triangle. Sine, cosine, secant, tangent, cosecant and cotangent are all functions however, the inverses are only a function when given a restricted domain.

Related Links:Math Trigonometry Inverse Tangent Function (Arctangent) Graphing a Sine Function |

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