Differentiation: (lesson 3 of 3)
Chain Rule
If y=f(u) is a differentiable function of u, and u=g(x) is a differentiable function of
x, then y=f(g(x)). This a differentiable function of x, and
dxdy=dudy⋅dxdu
or, equivalently,
dxd[f(g(x))]=f′(g(x))⋅g′(x)
Example 1:
yg(x)ydxdf=(x2+1)3, dxdy=?=u=x2+1,=f(u)=u3,=dudf⋅dxdu=(3u2)(2x)=3(x2+1)2(2x)=6x(x2+1)2
The General Power Rule
dxd[u(x)]n=n[u(x)]n−1⋅u′(x)
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The essence of mathematics is its freedom.
Geoge Cantor
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Black holes result from God dividing the universe by zero.
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