Question

what is the differentiation rule for (fg)(1)

Answer 1

sorry i didnt follow

Answer 2

well (fg)'(x) is f'(x) x g(x) + f(x) x g'(x)

when its written like (fg)(x)...what do you do

Answer 3

same as before

Answer 4

satellite that didnt work for me

Answer 5

dont know why

Answer 6

maybe you can post the exact question

Answer 7

fg(x)=(fog)(x)=f'[g(x)]*g'(x) so fg(1)= f'[g(1)]*g'(1

Answer 8

ok let met just do that here

Answer 9

nvm i think barbillus got it right

Answer 10

aaah
\[f\circ g\] got it!

Answer 11

http://en.wikipedia.org/wiki/Differentiation_rules

Answer 12

barbillus if at at 1 i have

f(x)= 1
f'(x)=-1
g(x)=2
g'(x)=3

Answer 13

am i doing -1(2) x (3)

Answer 14

f'(2)*3=-1*3=-3

Answer 15

my software rejected that

Answer 16

f'(g(x))*g'(x) ; f'(g(1))*g'(1) = f'(2)*3=-1*3=3 should be -3

Answer 17

pls look at that

Answer 18

ok let me check

Answer 19

it asks for fg(1) not its derivative f'g(1)
so we should put f(g(1))=f(2)=-3 again -3 i dunno why it is incorrect

Answer 20

i came up with -3 earlier and i agree with you

Answer 21

oh well thanks for the help

Answer 22

yea it's definitely -3

Answer 23

ill post it again on the main forum and see if anyone comes up with anything different

Answer 24

let me know if you get sth pls

Answer 25

what exactly is sth

Answer 26

or what does it mean

Answer 27

i mean please inform me

Answer 28

ok. im going to post it on the main forum. you just click and watch and see if anyone find anything different

Answer 29

or i can write here if someone get anything different

Answer 30

cool

Answer 31

pipa go here
http://openstudy.com/study#/updates/4f3b2dade4b0fc0c1a0ef37a

Answer 32

barbillus, the rule for (fg)(x) is just f x g. so the correct answer is 2
http://www.wolframalpha.com/input/?i=differentiate+%28fg%29%28x%29

Answer 33

oh thanks, i knew it as (fog)(x),,yeah then the result is 2