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48 A window is in the shape of a rectangle
Sorrounded by a semiciacle . If the Perimeter
of the window is
window is 20ff, find
2off, find the maxima
area :
Answers
Answered by
1
Step-by-step explanation:
Clearly, r=
2
l
Perimeter =P(rectangle )+ P(semi-circle)
=2(l+b)+πr
=r+2b+πr=20
⇒b=
2
20−r(1+π)
Area, A=lb+πr
2
=2rb+πr
2
=2r(20−r−rπ)+πr
2
=20r−r
2
⇒
dr
dA
=20−2r=0 at r=10
dr
2
d
2
A
=−2<0⇒ Maxima
⇒A
max
=200−100=100 ft
2
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