aron101782
New member
- Joined
- Jan 18, 2019
- Messages
- 26
I have a question about the derivation of the formula for the area of a circle to be pi r^2 .
When substituting for x I have used both r sint and r cost and both seem to work. However when using what would at first seem to be obviously correct x=rcost leads to a negative integrand and 0 as an upper bound of integration. My question is that is this the only reason why rsint is chosen as an arbitrary substitution.
-Aron
When substituting for x I have used both r sint and r cost and both seem to work. However when using what would at first seem to be obviously correct x=rcost leads to a negative integrand and 0 as an upper bound of integration. My question is that is this the only reason why rsint is chosen as an arbitrary substitution.
-Aron