A) 6, 12
B) 9, 9
C) 10, 8
D) 13, 5
Correct Answer: B
Solution :
Given \[2(a+b)=36\], \[a+b=18\] Area of rectangle \[=ab=a(18-a)\] \[A=18a-{{a}^{2}}\,,\,\,\therefore \frac{dA}{da}=18-2a\] Put \[\frac{dA}{da}=0\] i.e., \[18-2a=0\ \ \Rightarrow \,a=9;\,\ b=9\].You need to login to perform this action.
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