A Norman Window had the shape of a rectangle surmounted by a semicircle. If the perimeter of the window is 30ft, find the dimensions of the window so that the greatest possible amount of light is admitted. (maximize area)
http://imageshack.us/photo/my-images/163/normanwindow.jpg/

Question

A Norman Window had the shape of a rectangle surmounted by a semicircle. If the perimeter of the window is 30ft, find the dimensions of the window so that the greatest possible amount of light is admitted. (maximize area)
http://imageshack.us/photo/my-images/163/normanwindow.jpg/

jigglypuff314 · Answer

mmm my teacher says that x should be like 8 point something
but I keep getting 4 point something?
this is my work...

anonymous · Answer

well, apparently x is indeed 8.4 :D. Confirmed by wolfram alpha http://www.wolframalpha.com/input/?i=x%2830+-+x+-+%28pi%2F2%29x%29%2F2+%2B+%28pi%2F8%29x%5E2 You made a mistake somewhere

jigglypuff314 · Answer

yeah... I realized that XD
That's why I was asking.... ....
could you find where, or maybe point me in the right direction? :3

anonymous · Answer

hehe your mistake was (-pi/4)x^2 + (pi/8)x^2 isn't (-3pi/8)x^2

should be (-pi/8)x^2

jigglypuff314 · Answer

ohhhhhh okay, thank you! :)