integral95
Well-Known Member
- Joined
- Dec 16, 2012
- Messages
- 779
- Gender
- Male
- HSC
- 2013
yeah I know but which is the best to take?
essentially the identity to remove the value 1.The rule of thumb is when you have 1-cos(2x) you end up with 2sin^2(x)
And 1+cos(2x) gives 2cos^2(x)
You'll nee those identities when you learn to integrate sin^2(x) as well in the future.
Otherwise when you have cos(2x) by itself there is no rule of thumb. There's more intuition required for those. e.g. difference of two squares may mean I leave it in the original form cos^2(x)-sin^2(x)