- #1
shreddinglicks
- 216
- 6
Homework Statement
Find the points on the given curve where the tangent is horizontal or vertical
Homework Equations
r = 3cos(θ)
The Attempt at a Solution
d/dθ = -3sin(θ)
for horizontal:
-3sin(θ)sin(θ) + 3cos(θ)cos(θ)
I used identity and got:
3cos(2θ) = 0
I got the values PI/4, 3PI/4
How do I get the values 3/sqrt(2) and -3/sqrt(2)
to give me points (3/sqrt(2), Pi/4) and (-3/sqrt(2), Pi/4)