#### Michaelmoo

##### cbff...

- Joined
- Sep 23, 2008

- Messages
- 591

- Gender
- Male

- HSC
- 2009

Solve the following pair of parametrics:

x=2cosT and y=sinT for 0 Degrees < T < 180 degrees

Im finding that sometimes my circles/elipses are actually semi circles/elipses with these types of restrictions. Is this just using common sense or is there a way to derive this throughout the calculations?

Also if I write the equation for the complete circle/elipse with the y restriction near it (e.g. for -1 < y < 1), would I still get it correct? Or is it expected that I should manipulate the eqn itself?

Or in other words, please do the above equation with working.

Please help.

Thanks.