A) \[5\]
B) \[20\]
C) \[25\]
D) None of these
Correct Answer: C
Solution :
Given,\[x+y=10\] \[y=10-x\] ... (i) Now,\[f(x)=xy=x(10-x)=10x-{{x}^{2}}\] \[\therefore \] \[f'(x)=10-2x\] For maximum value of\[f(x)\], put\[f'(x)=0\] \[\Rightarrow \] \[10-2x=0\Rightarrow x=5\] \[\therefore \] \[x=5\]and\[y=5\][from Eq. (i)] Hence, maximum value of\[xy=5\times 5=25\]You need to login to perform this action.
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