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# Another Product rule differntiaion C3 watch

1. i have gotton down to:

I can't seem to simplyfy this one or have i gone wrong?

2. Make sure you're using the chain rule on (2x + 6)^4 to get V`, and then use the product rule
3. you haven't done product rule correctly.
4. (Original post by DeanK2)
you haven't done product rule correctly.
ok, i did it again and i got:

is this one right cos i can't seem to simpifly it either!
5. (Original post by DreamsComeTrue.)
ok, i did it again and i got:

is this one right cos i can't seem to simpifly it either!
Looks fine to me.
6. (Original post by Rocious)
Looks fine to me.
do you how to simplyfy this one?

it says in the book to take out of the brackets but i can't see how that works witht he second bit of the equation as i don't know how to take these complicated factors out!
7. No it's all wrong- i think!
8. You square the differential
9. Just start by taking x^2 out, and (2x+6)^3 out and see how it goes.
10. (Original post by PeeWeeDan)
Just start by taking x^2 out, and (2x+6)^3 out and see how it goes.
if i take out, then what happens to the as thats not a product of
11. (Original post by DreamsComeTrue.)
if i take out, then what happens to the as thats not a product of
3 times x^2 = 3x^2?
12. Square The Differential
13. (Original post by Rocious)
3 times x^2 = 3x^2?
oh yeah.. thats stupid of me!

Taking out gives..

=

then taking the 2 out gives:

does that work?
14. (Original post by DreamsComeTrue.)
oh yeah.. thats stupid of me!

Taking out gives..
Why only 4x?

Bearing in mind it's early, I could well be wrong.
15. (Original post by nicangeli)
Why only 4x?

Bearing in mind it's early, I could well be wrong.
oh yeah, my mistake:

=
taking out

yes! i think i've got it! thanks a lot!

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