Let a=x-ct and b=x+ct. Show that f_{ab}=f_{tt}-c^{2}f_{xx}. Hint: The chain rule for 2 varibles is d_{a}f(x,y)=f_{x}x_{a}+f_{y}y_{a.}

I'm assuming that f(a,b), a(x,t), and b(x,t).

Thanks in advance.

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- Aug 30th 2012, 08:24 PMkarebear688Chain Rule for 2 Variables
Let a=x-ct and b=x+ct. Show that f

_{ab}=f_{tt}-c^{2}f_{xx}. Hint: The chain rule for 2 varibles is d_{a}f(x,y)=f_{x}x_{a}+f_{y}y_{a.}

I'm assuming that f(a,b), a(x,t), and b(x,t).

Thanks in advance. - Sep 10th 2012, 02:49 AMchiroRe: Chain Rule for 2 Variables
Hey karebear688.

Show us what you have tried.