Monday, April 30, 2007

jason said...

How do you find the derivitive of a funtion that has more than one unknown variable?


Respond:
Excellent question!

Find dy/dx using implicit differentiation.

Step 1

We take the derivative of both sides to obtain

(x2) ′y + x2y′ + xy2 + x(y2) ′ = (3x) ′ .

Then, we simplify to

2xy + x2y′ + y2 + x2yy′ = 3

2xy + x2y′ + y2 + 2xyy′ = 3.

Step 2

Rearranging so that all terms containing y′ are on one side, we have

x2y′ + 2xyy′ = 3 – 2xyy2

y′ (x2 + 2xy) = 3 – 2xyy2

Step 3

Solve for y′ .


You can factor out x from the bottom if you like, but it doesn't really simplify the answer.





Also, go here for thje list aof all the general Calculus formulas you need to know.
http://www.calculus-help.com/funstuff/cheatsheet.html


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