Question

See attachment

Answer 1

I answer is choice (-9/4)

Answer 2

how do you get that? show me, please

Answer 3

When I got the second derivative it was (1/2x(x^2+1)^2

Answer 4

what is the first derivative?

Answer 5

It is 1/x^2+1

Answer 6

yes, and then second one?

Answer 7

is whatI typed above that

Answer 8

nope, some thing wrong, recheck, please

Answer 9

is it = (x^2+1) ^-1? take derivative of this,

Answer 10

It is (1/2x(x^2+1)^2

Answer 11

1st, lack of negative sign

Answer 12

second, 2x in numerator, not in denominator, right?

Answer 13

yes

Answer 14

so, at the end up, your answer should be?

Answer 15

(9/4)

Answer 16

I mean the form first , and then plug the number to make sure no mistake

Answer 17

f'(x)=1/(1+x^2)
f"(x)= -2x/(1+x^2)^2
put x=-2
f''(-2)=4/25

Answer 18

\[\frac{-2x}{(x^2+1)^2}\]

Answer 19

strongly agree with gorv

Answer 20

oh Loser66 I keep doing positives instead of - ok I came up with the answer 4/25 correct?

Answer 21

keep in mind, all the time, you have to have the form first, then, plug the number into it. that's the perfect way to avoid mistake

Answer 22

I don't calculate until the answer, I just give out the idea but I trust gorv when he gave out the neat way to get the answer, yours = his, I think it's ok,