Find all angles, 0^{\circ} \leq \theta<360^{\circ} , that satisfy the equation below, to the nearest tenth of a degree.4cos2θ+17cosθ+7=5cosθ+2Answer: θ=
Q. Find all angles, 0∘≤θ<360∘, that satisfy the equation below, to the nearest tenth of a degree.4cos2θ+17cosθ+7=5cosθ+2Answer: θ=
Simplify Equation: Simplify the given equation by moving all terms to one side to set the equation to zero.4cos2(θ)+17cos(θ)+7=5cos(θ)+24cos2(θ)+17cos(θ)+7−5cos(θ)−2=04cos2(θ)+12cos(θ)+5=0
Factor Quadratic: Factor the quadratic equation in terms of cos(θ). We are looking for factors of 4cos2(θ) and 5 that add up to 12cos(θ). (4cos(θ)+5)(cos(θ)+1)=0
Solve First Factor: Solve each factor for cos(θ).First factor: 4cos(θ)+5=0cos(θ)=−45Since the cosine of an angle cannot be less than −1 or greater than 1, this solution is not possible.
Solve Second Factor: Solve the second factor for cos(θ).Second factor: cos(θ)+1=0cos(θ)=−1
Find Angle: Find the angles θ that correspond to cos(θ)=−1. The cosine of an angle is equal to −1 at θ=180 degrees.
Check Range: Check the range for θ.Since we are looking for angles between 0 degrees and 360 degrees, the only angle that satisfies the equation and is within the range is θ=180 degrees.
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