Question

is there a point of inflection of function f(x)=-6x+4cosx on the interval [0,2pi], if so can you tell me what it is?

Answer 1

you are given f(x)

what is the first derivative, f ' (x) ?

Answer 2

-6-4sinx
f''(x)=-4cos x

Answer 3

correct on both

Answer 4

now set f '' (x) equal to zero and solve for x. What do you get?

Answer 5

pi/2?

Answer 6

what else

Answer 7

yes pi/2

Answer 8

3pi/2

Answer 9

good

Answer 10

now you need to set up a sign chart to see if f '' changes sign as you pass through these critical points

Answer 11

oh k thank you, yea i know how to find them just got stuck on the inflection thank you for the help

Answer 12

ok great, yw