Question

Find the slope of the tangent line to the curve y = cos(2x) when x = pi/6?

Answer 1

are u stuck ? u know how to start ?

Answer 2

I found the derivative to by y' = -2sin2x, but I don't think that's right.

Answer 3

that is actually correct.

Answer 4

now just put x = pi/6
and u get the slope .

Answer 5

y' = -2sin(2x)
y' = -2sin(2pi/6)
y' = -2sin(pi/3)
y' = -2(0)
y' = 0 ?

Answer 6

sin pi/3 = ?
its not 0.

Answer 7

Oh my bad, sin pi/3 = sqrt(3)/2

Answer 8

So -sqrt(3) since the 2s cancel out?

Answer 9

that is correct!

Answer 10

Thank you very much for taking my through the process!

Answer 11

welcome ^_^