Question

Find the value of (f ◦ g)' at the given value of x (attachment)

Answer 1

1/6

Answer 2

u equals 7x-x^2, so you can substitute that any place where u is.

Answer 3

so f(x) = 1/ 7x-x^2

Answer 4

And since x=1, you can substitue that in anywhere

Answer 5

thats not an answer choice.

1/5
-1/5
-5/36
5/36

Answer 6

so f(1) = 1/(7(1)-1^2)

1/6

Answer 7

Oh

Answer 8

Hm

Answer 9

Could it be that your teacher made a typo?

Answer 10

Or when you say (f ◦ g)', is that asking for the derivative? I assumed it was a typo?

Answer 11

i dont know. the derivative of 1/6 is 0....

Answer 12

Ah, but if you take the derivative of 1/(7x-x^2) and then plug in 1

Answer 13

I'll bet that's your answer. I though that ' was a typo.

Answer 14

So to take the derivative of (7x-x^2)^-1 we're going to need to use the chain rule

So I like to work outside inwards, so outside we find

-(7x-x^2)^-2 times the inside derivative

Answer 15

-(7x-x^2)^-2 (7-2x)

Answer 16

and then plug in 1

Answer 17

ok i got -5/36. thank you so much!

Answer 18

No problem