When you're working with the chain rule and composite functions, you work from the outside in.
The Chain Rule is defined as
d/dx[f(g(x))] = f ' (g(x)) * g'(x)
(derivative of the outside, recopy the inside multiplied by the derivative of the inside)
Example:
2 * 8th root of (9-x^2)
2 * (9-x^2)^(1/8)
2 * (1/8)(9-x^2)^(-7/8) * (-2x)
(-x/2)(9-x^2)^(-7/8)
(((-x)/(2)))/(((9-x^2)^(7/8))/(1))
((-x))/(2(9-x^2)^(7/8)) FINAL ANSWER
I already said what I didn't understand in the top of the blog. Some examples of Chain Rule and quotient rule used in different occasions would be nice, especially with trig functions.
Stephen,
ReplyDeleteTo help you with the chain rule. You use the chain rule any time there is something besides an x in an equation.
EX
(x^2 +1) ^ 3
sqrt(sinx)
sin(x^2)
All of these examples don't have an x being raised to an exponent, inside a sqrt, etc.