Question

Calculus question?

Answer 1

On #34, the answer book shows 3pi/4 as the x value for the point. Why can't pi/4 be an answer as well?

Answer 2

I took the derivative and got:
\[e^x(cosx + sinx)\]
To make that equal zero, wouldn't both pi/4 and 3pi/4 do that?

Answer 3

why would \(\pi/4\) work?

Answer 4

cos (pi/4)=sin(pi/4), so cos(pi/4)+sin(pi/4) is not 0

Answer 5

right it is not zero...so it doesn't have a horizontal tangent there

Answer 6

you want all the places where the derivative IS zero

Answer 7

Ahh, okay! Thanks