maths p1

[mehak]

can some one help me with maths pi nov/o8 question 7 part i and question number 9 part ii

 

[SZ11]

for q9 pii:
find volume when y=2 is rotated through 360 degrees with limits of 0 and 1
then subtract the volume obtained when the curve is rotated through 360 with limits of 0 and 1.
that will give you volume of the shaded region.

q7 pi)
let length of one piece = l
other piece = 80 - l

perimeter of square = 4x
thus l = 4x

perimeter of circle = 80 - l
thus 2(pi)(r) = 80 - l

equating.
2(pi)(r) = 80 - 4x
thus (r) = (40-2x)/(pi)

Area = x^2 + (pi) * [(40 -2x)/(pi)]^2

simplify this and you'll end up with the answer...