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Mathematics 17 Online
OpenStudy (fanduekisses):

CALCULUS HELP!!! PLEASE

OpenStudy (fanduekisses):

Given f and g are differentiable function and f(a)=-4, g(a)=c, g(c)=10, f(c)=15, f'(a)=8, g'(c)=5, f'(c)=6 If h(x)=f(g(x)), find h'(a)

zepdrix (zepdrix):

Hey there :) Remember how to apply your chain rule?

OpenStudy (fanduekisses):

yes

zepdrix (zepdrix):

\[\Large\rm \frac{d}{dx}f(g(x))=f'(g(x))\cdot g'(x)\]This look familiar? This is how we differentiate a composition.

zepdrix (zepdrix):

Therefore if,\[\Large\rm h(x)=f(g(x))\]Then,\[\Large\rm h'(x)=f'(g(x))\cdot g'(x)\]

zepdrix (zepdrix):

And we want to evaluate this function h at x=a.

zepdrix (zepdrix):

\[\Large\rm h'(\color{orangered}{a})=f'(g(\color{orangered}{a}))\cdot g'(\color{orangered}{a})\]

zepdrix (zepdrix):

Hmm let's start on the right side. g'(a) = ?

zepdrix (zepdrix):

Oh they didn't give us that :O Interestingggg

OpenStudy (fanduekisses):

b

zepdrix (zepdrix):

b? Ok I'll take your word for it :D It's not listed above, but maybe you forgot to list some of them.

zepdrix (zepdrix):

\[\Large\rm h'(\color{orangered}{a})=f'(g(\color{orangered}{a}))\cdot b\]

zepdrix (zepdrix):

For a composition, work from the inside outward.\[\Large\rm h'(a)=f'(\color{royalblue}{g(a)})\cdot b\]How bout that g(a) part? Can we replace it with something?

OpenStudy (fanduekisses):

c

zepdrix (zepdrix):

\[\Large\rm h'(a)=f'(\color{royalblue}{c})\cdot b\]Good good good.

OpenStudy (fanduekisses):

so it is 6b! :D

zepdrix (zepdrix):

Yay team! \c:/ Good job!

OpenStudy (fanduekisses):

thanks

zepdrix (zepdrix):

no probsss

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