, so
, so
, so
.
NOW, use the trigonometry formula , and plug in what we just found.
, so
, so
.
You could rewrite that as:
.
Did that help?
An example with answer I have goes;
x = 6 cos t
y = sqrt 11 sin t
Write down the equation of the conic & state what type of conic it is.
trig identity cos^{2}t + sin^{2}t = 1
which gives
x^{2} / 6^{2} + y^{2} / (sqrt 11)^{2} = 1 . . . . . . . .
er! how does this happen, if you could help!