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Find all angles, 
0^(@) <= theta < 360^(@), that satisfy the equation below, to the nearest tenth of a degree.

-4cos^(2)theta+13 cos theta-5=9cos theta-8
Answer: 
theta=

Find all angles, 0θ<360 0^{\circ} \leq \theta<360^{\circ} , that satisfy the equation below, to the nearest tenth of a degree.\newline4cos2θ+13cosθ5=9cosθ8 -4 \cos ^{2} \theta+13 \cos \theta-5=9 \cos \theta-8 \newlineAnswer: θ= \theta=

Full solution

Q. Find all angles, 0θ<360 0^{\circ} \leq \theta<360^{\circ} , that satisfy the equation below, to the nearest tenth of a degree.\newline4cos2θ+13cosθ5=9cosθ8 -4 \cos ^{2} \theta+13 \cos \theta-5=9 \cos \theta-8 \newlineAnswer: θ= \theta=
  1. Rewrite Equation: First, let's rewrite the given equation to collect like terms on one side:\newline4cos2(θ)+13cos(θ)5=9cos(θ)8-4\cos^2(\theta) + 13\cos(\theta) - 5 = 9\cos(\theta) - 8
  2. Combine Like Terms: Now, subtract 9cos(θ)9\cos(\theta) from both sides and add 88 to both sides to get all terms involving cos(θ)\cos(\theta) on one side and the constant on the other side:\newline4cos2(θ)+13cos(θ)59cos(θ)+8=0-4\cos^2(\theta) + 13\cos(\theta) - 5 - 9\cos(\theta) + 8 = 0
  3. Quadratic Equation: Simplify the equation by combining like terms: \newline4cos2(θ)+4cos(θ)+3=0-4\cos^2(\theta) + 4\cos(\theta) + 3 = 0
  4. Factorize: This is a quadratic equation in terms of cos(θ)\cos(\theta). Let's set u=cos(θ)u = \cos(\theta) to make it easier to solve:\newline4u2+4u+3=0-4u^2 + 4u + 3 = 0
  5. Solve for uu: Now, we can factor the quadratic equation:\newline4u2+4u+3=0-4u^2 + 4u + 3 = 0\newline(2u+1)(2u+3)=0(2u + 1)(-2u + 3) = 0
  6. Find Possible Values: Set each factor equal to zero and solve for uu:2u+1=02u + 1 = 0 or 2u+3=0-2u + 3 = 0
  7. Discard Invalid Value: Solve the first equation for uu:2u+1=02u + 1 = 02u=12u = -1u=12u = -\frac{1}{2}
  8. Find Corresponding Angles: Solve the second equation for uu:\(\newline\)2-2uu + 33 = 00\(\newline\)2-2uu = 3-3\(\newline\)uu = 32\frac{3}{2}
  9. Final Answer: Since u=cos(θ)u = \cos(\theta), we have two possible values for cos(θ)\cos(\theta): 12-\frac{1}{2} and 32\frac{3}{2}. However, the cosine of an angle cannot be greater than 11, so we discard the value 32\frac{3}{2}.
  10. Final Answer: Since u=cos(θ)u = \cos(\theta), we have two possible values for cos(θ)\cos(\theta): 12-\frac{1}{2} and 32\frac{3}{2}. However, the cosine of an angle cannot be greater than 11, so we discard the value 32\frac{3}{2}.Now we find the angles θ\theta that correspond to cos(θ)=12\cos(\theta) = -\frac{1}{2}. The cosine of 12-\frac{1}{2} occurs at 120120 degrees and cos(θ)\cos(\theta)00 degrees in the range of cos(θ)\cos(\theta)11 to cos(θ)\cos(\theta)22 degrees.
  11. Final Answer: Since u=cos(θ)u = \cos(\theta), we have two possible values for cos(θ)\cos(\theta): 12-\frac{1}{2} and 32\frac{3}{2}. However, the cosine of an angle cannot be greater than 11, so we discard the value 32\frac{3}{2}.Now we find the angles θ\theta that correspond to cos(θ)=12\cos(\theta) = -\frac{1}{2}. The cosine of 12-\frac{1}{2} occurs at 120120 degrees and cos(θ)\cos(\theta)00 degrees in the range of cos(θ)\cos(\theta)11 to cos(θ)\cos(\theta)22 degrees.We can now write the final answer with the angles that satisfy the original equation:\newlinecos(θ)\cos(\theta)33 degrees, cos(θ)\cos(\theta)00 degrees

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