Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If x, y are acute angles, where 0 < x + y < 90° and sin (3x - 40°) = cos(3y + 40°), then the value of tan(x + y) is equal to:

Options:

$\frac{1}{\sqrt{2}}$

$\frac{1}{\sqrt{3}}$

1

$\frac{1}{3}$

Correct Answer:

$\frac{1}{\sqrt{3}}$

Explanation:

sin (3x - 40°) = cos(3y + 40°)

Formula used :-

sin A = cos B

Then , A + B = 90º

So, ( 3x - 40º  + 3y + 40º ) = 90º 

x + y = 30º 

Now,  tan( x + y )

= tan30º 

=  \(\frac{1 }{ √3 }\)