how to find the value of a derivative at the given point?

Question

zubhanwc3 · Answer

the function was f(x) = 2+cosx
the deriv is 3-sinx

point is (pi,-1)

zubhanwc3 · Answer

er
function was f(x) - 2+3cosx

zubhanwc3 · Answer

is the value 3?

snowfire · Answer

How did you get the 3 in the "3-sinx"?

snowfire · Answer

Derivatives of sums are simply the derivatives of the two terms being added individually. So the derivative of 2+cosx is the derivative of 2 plus the derivative of cosx.

zubhanwc3 · Answer

by plugging in pi for x

zubhanwc3 · Answer

o
i used wolfram alpha

zubhanwc3 · Answer

and followed the steps shown there

i just need to know if i should plug in 3 for

snowfire · Answer

Okay well that would be the easy way out, and you wouldn't learn anything ^^ You want to find the derivative of the function first, then plug in the point into that derivative function.

zubhanwc3 · Answer

tyvm