Q. Find all angles, 0∘≤θ<360∘, that satisfy the equation below, to the nearest tenth of a degree.cos2θ−cosθ−12=0Answer: θ=
Solve Quadratic Equation: Let's first solve the quadratic equation in terms of cos(θ). The equation is cos2(θ)−cos(θ)−12=0. We can treat cos(θ) as a variable, say 'u', and rewrite the equation as u2−u−12=0. Now we can factor this quadratic equation.
Factor Quadratic Equation: To factor the quadratic equation u2−u−12=0, we look for two numbers that multiply to −12 and add up to −1. These numbers are −4 and 3. So we can write the equation as (u−4)(u+3)=0.
Identify Valid Solutions: Now we have two possible solutions for u: u−4=0 or u+3=0. Solving for u gives us u=4 or u=−3. However, since u represents cos(θ) and the range of the cosine function is [−1,1], u=4 is not a valid solution. Therefore, we only consider u=−3, but again, this is outside the range of the cosine function, so there are no solutions in terms of cosine.
Conclude No Solutions: Since there are no valid solutions for cos(θ) in the range [−1,1], we conclude that there are no angles θ between 0 and 360 degrees that satisfy the original equation cos2(θ)−cos(θ)−12=0.
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