x= 9cos(theta) - 2cos^2 (theta)
y= 9sin(theta) - 2sin(theta)cos(theta)
find the slope

for some reason i wanted to substitute something in for cos^2(theta) like 1/2 cos(2theta) + 1/2.
for some reason, when i do this substitution i get a different slope. please help

Question

x= 9cos(theta) - 2cos^2 (theta)
y= 9sin(theta) - 2sin(theta)cos(theta)
find the slope

for some reason i wanted to substitute something in for cos^2(theta) like 1/2 cos(2theta) + 1/2. 
for some reason, when i do this substitution i get a different slope. please help

anonymous · Answer

$$x = 9\cos(\theta) - 2 \cos^2(\theta)$$
$$y = 9\sin(\theta) - 2\sin(\theta)\cos(\theta)$$

Right?

anonymous · Answer

yes