- #1
spacetimedude
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Homework Statement
Find the gradient of [tex]\underline{\nabla}(\underline{a}\cdot\underline{r})^n[/tex] where a is a constant vector, using suffix notation and chain rule.
Homework Equations
On the previous problem,s I found that grad(a.r)=a and grad(r)=[itex]\underline{\hat{r}}[/itex]
The Attempt at a Solution
[tex]
\underline{e_i}(\frac{\partial }{\partial x_i})(\underline{a}\cdot\underline{r})^n=\underline{e_i}(\frac{\partial }{\partial x_i}(a_jx_j)^n)=\underline{e_i}(n(a_jx_j)^{n-1}(a_j\delta_{ij}))
[/tex]
I'm sure that the last step is wrong so could someone lead me to the right direction?
Thank you!
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