# Solving Trigonometric Equations In Given Intervals

## Understanding Trigonometric Equations

• A trigonometric equation is a type of equation that involves trigonometric functions, such as sin, cos, or tan.

• Solving these types of equations typically involves finding the angles that make the equation true.

• These equations can have one solution, multiple solutions, or no solutions, depending on the given interval.

## The Importance of Intervals

• The given interval indicates the range of possible solutions for a trigonometric equation.

• Trigonometric functions are periodic, so without a given interval, an equation could have an infinite number of solutions.

• The interval indicates the start and end point for the solutions. For example, an interval from 0 to 360 degrees or from 0 to 2π radians indicates that we are looking for angles within one complete rotation.

## Solving Methods

• One of the first steps in solving a trigonometric equation can be to rewrite the equation in terms of a single trigonometric function if possible.

• To solve for an unknown angle, the inverse trigonometric functions sin⁻¹(x), cos⁻¹(x), and tan⁻¹(x) are often used.

• The solutions may need to be expressed in degrees, radians, or both.

• Use trigonometric identities to simplify or rewrite the equation, making it easier to solve.

## Considering Solutions Outside the Given Interval

• Remember that the trigonometric functions repeat their values in cycles: every 360 degrees or 2π radians for sine and cosine, and every 180 degrees or π radians for tangent.

• Because of this, an equation could have solutions that are outside the given interval.

• However, if a solution lies outside the given interval, it should not be included in the answers.

## Summarizing the Solutions

• When the solution method yields multiple solutions within the given interval, all these values should be included in the final answer.

• Be sure to check that each purported solution actually satisfies the original equation.

• Even if the equation is very complicated, the method of solving is generally to simplify, use identities to rewrite the equation, use inverse trigonometric functions to solve for the missing angle(s), and check all purported solutions.