Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If tan2A + 2tanA - 63 = 0 Given that 0 < A < $\frac{\pi}{2}$  what is the value of ( 2sinA + 5cosA)?

Options:

$19\sqrt{50}$

$15\sqrt{50}$

$\frac{19}{\sqrt{50}}$

$\frac{15}{\sqrt{50}}$

Correct Answer:

$\frac{19}{\sqrt{50}}$

Explanation:

tan2A + 2tanA - 63 = 0

tan2A +9tanA - 7tanA - 63 = 0

on solving ,

tanA = \(\frac{7}{1}\)

By using pythagoras theorem ,

P2 + B2 = H2

72 + 12 = H2

H = √50

Now , ( 2sinA + 5cosA)

= 2 ( \(\frac{7}{√50}\)  ) + 5 ( \(\frac{1}{√50}\)  )

\(\frac{19}{√50}\)