Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If sin x - cos x = 0, then the value of $(sin^3x - cos^3x)$ is :

Options:

0

2

1

4

Correct Answer:

0

Explanation:

Using :-

sinA = cosB  Iff  A + B = 90º

As,  sinx - cosx = 0

⇒ sinx = cosx

⇒ x + x = 90º

⇒ x = 45º

Now,

sin³x - cos³x

= sin³45º - cos³45º

= ( \(\frac{1 }{√2}\) )³ - ( \(\frac{1 }{√2}\) )³

= 0