Applications Of Derivatives Question 357

Question: The two parts of 100 for which the sum of double of first and square of second part is minimum, are

Options:

A) 50, 50

B) 99, 1

C) 98, 2

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

Let one number is $ (100-x) $ and then another is x. Therefore $ f(x)=2(100-x)+x^{2}=x^{2}-2x+200 $

$ f’(x)=0\Rightarrow 2x-2=0\Rightarrow x=1 $

Here $ {f}’’,(x)=2>0 $ Therefore function is minimum at $ x=1 $ So the numbers are 99 and 1.