Differentiation Question 27

Question: If $ \underset{x\to \infty }{\mathop{\lim }}{ \frac{x^{3}+1}{x^{2}+1}-(ax+b) }=2 $ , then

Options:

A) $ a=1,b=1 $

B) $ a=1,b=2 $

C) $ a=1,v=-2 $

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

[c] $ \underset{x\to \infty }{\mathop{\lim }}( \frac{x^{3}+1}{x^{2}+1}-(ax+b) )=2 $ Or $ \underset{x\to \infty }{\mathop{\lim }}\frac{x^{3}(1-a)-bx^{3}-ax+(1-b)}{x^{2}+1}=2 $ Or $ 1-a=0 $ and $ -b=2 $ Or $ a=1, $

$ b=-2 $