Inverse sines and cosines Evaluate or simplify the following expressions without using a calculator.


sin⁻¹ ( -1 )

Key Concepts

Inverse Trigonometric Functions

Inverse trigonometric functions, such as sin⁻¹ (arcsin) and cos⁻¹ (arccos), are used to find angles when the value of a sine or cosine is known. For example, sin⁻¹(x) gives the angle whose sine is x, with a principal range typically between -π/2 and π/2 for arcsin. Understanding these functions is crucial for evaluating expressions involving inverse trigonometric values.

Range of Inverse Sine Function

The range of the inverse sine function, sin⁻¹(x), is limited to the interval [-π/2, π/2]. This means that when evaluating sin⁻¹(-1), we are looking for an angle within this range whose sine value is -1. Recognizing this range helps in determining the correct angle corresponding to the given sine value.

Unit Circle

The unit circle is a fundamental concept in trigonometry that helps visualize the values of sine and cosine for various angles. It is a circle with a radius of one centered at the origin of a coordinate plane. The sine of an angle corresponds to the y-coordinate of the point on the unit circle, which aids in understanding why sin⁻¹(-1) equals -π/2, as this is the angle where the sine value reaches its minimum.