Maths equation help URGENT!! (1 Viewer)

360flip

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imdoing tutor hw and i cant do a single question because ive completely forgotten an differentiation equation and i ripped my old notes by accident and returned my yr 11 textbook and the equation had something like second derviative with u u' v v' something like (u')v-u(v') or something can someone correct me on this and give me examples! please reply quickly my tutor hw is due soon!
 

Raginsheep

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You're looking for the divisor rule I assume.

d/dx u/v= vu'-uv'.
 
P

pLuvia

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Product rule
y' = uv' + vu'

Example
Differentiate y=2x(x-1) (Note you can just expand and use chain rule)
u=2x
v=x-1

y'= 2x(1) + (x-1)2
= 3x-2

Quotient rule
y' = (vu' - uv') / v2

Example
Differentiate y = x2-1/x
u=x2-1
v=x

y' = [x(2x) - (x2-1)] / x2
= x2+1/x2

Edit: Please don't bump this thread so many time, no one will answer in like 5 mins give it time
 

Riviet

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Firstly, there is absolutely no need to be bumping a newly started thread by the minute! Someone will come around to helping you; in future please be patient. ;)

I personally find it to remember it verbally rather than with u's and v's.

Try remembering it like this:

"The bottom function multiplied by the derivative of the top function, minus the top function multiplied by the derivative of the bottom function, ALL OVER the bottom function squared."

Now shortening it significantly:

"The bottom by the derivative of the top, minus the top by the derivative of the bottom, all over the bottom squared." (what I say in my head)
 

Mountain.Dew

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u could try this:

(1) u = .....
(2) u' = .....
(3) v = ......
(4) v' = .....

so, quotient rule is: F(x) = inside - outside/ (bottom function)^2. Inside is (2)*(3) and outside is (1)*(4)
 

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