Q. Find all angles, 0∘≤θ<360∘, that satisfy the equation below, to the nearest tenth of a degree.cos2θ−1=0Answer: θ=
Recognize Pythagorean Identity: To solve the equation cos2(θ)−1=0, we first need to recognize that this is a Pythagorean identity. The identity is cos2(θ)=1−sin2(θ), but since we have cos2(θ)−1=0, we can rewrite it as cos2(θ)=1.
Take Square Root: Next, we take the square root of both sides of the equation to solve for cos(θ). This gives us two possible equations: cos(θ)=1 and cos(θ)=−1, because the square root of 1 is both 1 and −1.
Find Cosine of 1: We now find the angles where the cosine is equal to 1. The cosine of an angle is equal to 1 at 0 degrees (or 0 radians). This is the only angle between 0 degrees and 360 degrees where the cosine is 1.
Find Cosine of −1: Next, we find the angles where the cosine is equal to −1. The cosine of an angle is equal to −1 at 180 degrees (or π radians). This is the only angle between 0 degrees and 360 degrees where the cosine is −1.
Identify Satisfying Angles: We have found all the angles that satisfy the equation cos2(θ)−1=0. These angles are 0 degrees and 180 degrees. There are no other angles in the range from 0 degrees to 360 degrees that satisfy the equation.
More problems from Csc, sec, and cot of special angles