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MHT CET · Maths · Application of Derivatives

10 is divided into two parts such that the sum of double of the first and square of the other is minimum, then the numbers are respectively

  1. A 9,1
  2. B 8,2
  3. C 6,4
  4. D 7,3
Verified Solution

Answer & Solution

Correct Answer

(A) 9,1

Step-by-step Solution

Detailed explanation

Let the two parts of 10 be \(x\) and \((10-x)\).
\(
f(x)=2(10-x)+x^2=x^2-2 x+20
\)
\(f^{\prime}(x)=2 x-2\) and when \(f^{\prime}(x)=0\), we get \(x=1\)
\(
\mathrm{f}^{\prime \prime}(\mathrm{x})=2>0
\)
\(\therefore \mathrm{f}(\mathrm{x})\) is minimum at \(\mathrm{x}=1\).
Thus the parts are 1,9 .