Differentiate (2 Viewers)

[ameh]

This is how a friend and I remembered the quotient and product rule's in differentiation, It's a weird method but hey it's stuck in my memory!:

Quotient Rule:

very ugly dash - ugly very dash
over very squared

Product Rule:

ugly very dash - very ugly dash


[you get the picture, it's not very conventional but it worked for me!]

 

[speed2]

Product Rule:

ugly very dash - very ugly dash


[you get the picture, it's not very conventional but it worked for me!]

isnt it "+" for product rule??

 

[kami]

that just complicates things so much its not funny. sorry, but i had to say. what dreamerish said is all you need to know, in perfect format.

What Dreamerish has said verges on flawless and it is all that many will need to know, however in related rates of change in 2u as well as other things in the higher courses you need to know how to chain these things as shown in Templar's example - dy/dx = du/dx * dy/du.

As for memorising techniques, I learned (Video - Deviant)/v^2 for the quotient rule...which isn't perfect, but it works for me. And from that I just tinkered with things to get the product rule or the by parts method.

 

[jessied]

1st times the derivative of the 2nd + the 2nd times the derivative of the 1st.

i've never learnt that v u crap...:/

lol. That's how I remember it too.. always thought that v and u crap was a waste of time..

to remember the quotient rule.. bottom thing times the derivative of the top minus the top times the derivative of the bottom over the bottom suqared.. made both of them into a little song.. works a charm!

 

[insert-username]

by first principles

lim h-->infinity

(f(x + h) - f(x))/h


Have fun differentiating (x² + 4)(3x² - 2x)^6 by first principles.


I_F

 

[rama_v]

lol its lim x-> 0 not x->infinity. Youd be measuring the gradient of an infinite secant otherwise

 

[haboozin]

lol its lim x-> 0 not x->infinity. Youd be measuring the gradient of an infinite secant otherwise

haha oops...

well h-->0


i still like my method of poly divisions better than Q rule.

 

[ameh]

isnt it "+" for product rule??

yup, sorry my mistake!