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differentiation

find the 2nd derivative of:

y= (4x+12)/(x^2+6x+12)

and find the values of x for which the 2nd derivative = 0

I think i've got the 2nd derivative but am not sure. and i dont knw how to solve the resultant polynomial to find the values of x as it is a 5th order polynomial i think. unless i have made a mistake.

PLEASE SOM1 HELP!!

Reply 1

inactive__user

i got 2nd derivative as (8x + 24)/(x^2+6x+12)^2

meaning x = -3

i may well be wrong as i havent done it thoroughly

Reply 2

Cirsium

Ummm sorry gonna have to ask the obvious question....
started doing this....tried to factorise x^2+6x+12 .... and couldn't. And then i realised y.... b^2 < 4ac - therefore that has no real routes :frown:

I'm probably missing sumthing really obvious then like quotient rule.... but i'm tired :frown:

Reply 3

inactive__user

ye you just have to slog it out with quoient (or product rule which i personally prefer). i know im so tired 2...just cant stop stressing bout oxford!