Find an equation of the tangent line to
the graph of at the given point. MEDAL WILL BE REWARDED!!!!
y=cos3x
(pi/4, sqrt2/2)

Question

Find an equation of the tangent line to
the graph of at the given point. MEDAL WILL BE REWARDED!!!!
y=cos3x 
(pi/4, sqrt2/2)

isaiah.feynman · Answer

Find the derivative of y=cos3x, then substitute pi/4 for x, what ever you get is the SLOPE. Then using y-y1=m(x-x1) get the equation of the line by making the necessary substitutions!

anonymous · Answer

okay so is the derivative 0?

anonymous · Answer

or is it -3sin3x?

isaiah.feynman · Answer

Its -3sin3x.

anonymous · Answer

okay so my final answer is y=1, y=.9865?

isaiah.feynman · Answer

No y' = 0.123. That's the slope!

anonymous · Answer

so how do I plus that into the point slope form?

isaiah.feynman · Answer

And the slope is negative because of that minus sign.

isaiah.feynman · Answer

To put it in point slope form do the following substitution y1=sqrt2/2 m=-0.123, and x2=pi/4.