Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If sin A = $\frac{4}{5}$ and sin B = $\frac{15}{17}$, what is the value of sin(A - B) ?

Options:

$-\frac{32}{45}$

$-\frac{13}{85}$

$\frac{13}{85}$

$\frac{32}{45}$

Correct Answer:

$-\frac{13}{85}$

Explanation:

sinA = \(\frac{4}{5}\)                              sinB = \(\frac{15}{17}\) 

By using pythagoras theorem ,           By using pythagoras theorem ,

P2 + B2 = H2                                            P2 + B2 = H2                                         42 + B2 = 52                                            152 + B2 = 172

B = 3                                                           B = 8

cos A = \(\frac{3}{5}\)                    cos B = \(\frac{8}{17}\) 

sin ( A - B ) = sinA cosB - cosA sinB

= \(\frac{4}{5}\)  × \(\frac{8}{17}\)  - \(\frac{3}{5}\) × \(\frac{15}{17}\) 

= \(\frac{32}{85}\)  - \(\frac{45}{85}\) 

- \(\frac{13}{85}\)