Faraz R. answered • 11/14/16

Tutor

4.9
(530)
RANKED TOP 1% IN 2019 AP SAT SUBJECT TEST PREP MATH AND SCIENCE TUTOR.

169=xy

2(4x)+2(4y)=C(x)

169/x=y

8x + 8(169/x)=C(x)

Take 1st derivative.

8 - 1352/x

^{2}=C'(x)Set C'(x)=0

and you get

-1352=-8x

^{2}Solve by dividng by -8 to get x

^{2}=169. Take square root and you will get x = 13. Plug 13 into 169=13y. You get y = 13.Your dimensions should be 13 x 13.