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## Main Question or Discussion Point

if you want to find the derivative (gradient) of f(x)^2 when f is a vector, you would get

2*f(x)*del(f(x))

I never know where to put the transpose!! sometimes its clear because another term in the equation will be a scalar, so you know an inner product is needed, but if you dont have a hint like that, how do you know if you should put the transpose on the f(x) or the del(f(x))? I suppose it depends on if f is a column or row vector, but alot of times this is not given in the statement of the problem.

Any thoughts on this? Does anyone have a good online tutorial on vector/matrix differentiation?

Thanks!

Dave

2*f(x)*del(f(x))

I never know where to put the transpose!! sometimes its clear because another term in the equation will be a scalar, so you know an inner product is needed, but if you dont have a hint like that, how do you know if you should put the transpose on the f(x) or the del(f(x))? I suppose it depends on if f is a column or row vector, but alot of times this is not given in the statement of the problem.

Any thoughts on this? Does anyone have a good online tutorial on vector/matrix differentiation?

Thanks!

Dave