If \frac{\cos^{2}\theta-3\cos\theta+2}{\sin^{2}\theta}=1, where 0^{\circ} \lt \theta \lt 90^{\circ}, then what is \sin^{2}\theta+\cos\theta equal to?
- A. \frac{5}{4} ✓
- B. \frac{3}{2}
- C. \frac{7}{4}
- D. 2
Correct Answer: A. \frac{5}{4}
Explanation
Substitute \sin^2\theta = 1 - \cos^2\theta, so \cos^2\theta - 3\cos\theta + 2 = 1 - \cos^2\theta. Rearranging gives 2\cos^2\theta - 3\cos\theta + 1 = 0, factoring to (2\cos\theta - 1)(\cos\theta - 1) = 0. Since \theta \neq 0, \cos\theta = \frac{1}{2} \implies \theta = 60^{\circ}. Thus, \sin^2 60^{\circ} + \cos 60^{\circ} = \frac{3}{4} + \frac{1}{2} = \frac{5}{4}.
Related questions on Trigonometry
- Two poles are situated 24 m apart and their heights differ by 10 m. What is the distance between their tips?
- If \frac{\cos \theta}{1 - \sin \theta} + \frac{\cos \theta}{1 + \sin \theta} = 4, then which one of the following is a value of $(\tan^2 \...
- For 0 < \theta < \frac{\pi}{2}, consider the following : I. $(\tan^4 \theta + \tan^6 \theta)(\cot^4 \theta + \cot^6 \theta) = \sec^2 \the...
- If 3\sin \theta + 4\cos \theta = 5, then what is a value of 4\tan \theta + 3\cot \theta ?
- At a point on level ground, the tangent of the angle of elevation of the top of a tower is found to be \frac{5}{6}. On walking 70 m toward...