Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Continuity and Differentiability

Question:

$\underset{x→∞}{\lim}\frac{\sin^4x-\sin^2x+1}{\cos^4x-\cos^2x+1}$ is equal to

Options:

0

1

1/3

1/2

Correct Answer:

1

Explanation:

$\sin^4x-\sin^2x+1$

$=(1-\cos^2x)^2-(1-\cos^2x)+1=1+\cos^4x-\cos^2x⇒\frac{\sin^4x-\sin^2x+1}{\cos^4x-\cos^2x+1}=1$

Thus given limit is equal to one.