- #1
vande060
- 186
- 0
Homework Statement
find the region enclosed by astroid
x= acosϑ 3
y=asinϑ 3
the astroid looks like this picture in my book, with the shaded region stretching for x (-a,a)
and for y(-a,a)
Homework Equations
i think the formula is ... from (-a to a) ∫ y * x' dϑ
The Attempt at a Solution
a = ∫ acosϑ 3 * 3asinϑ 2 cosϑ
a = 3a2∫ cosϑ 4 * sinϑ 2
a = 3a2∫ cosϑ 4 * (1-cosϑ 2 )
a = 3a2∫ cosϑ 4 - cosϑ6
is this one the right track, if so I can evaluate the rest of that integral myself