Computing Inner Products in C: Simplifying Complex Vector Calculations

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Homework Statement

x=(2,1+i,i) and y=(2-i,2,1+2i)



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The Attempt at a Solution

um ok normally i would use <a,b>=|a||b|cos(theta). But these are complex numbers. I have no clue how to do this.
 
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Surely you have a definition to appeal to?

(and I'm pretty sure that <a,b>=|a||b|cos(theta) isn't it -- and even if that equation were correct, it is rare that you'd actually want to use it to compute an inner product)
 
Suppose instead you were just working with real vectors -- say (2,20,2) and (10,1,1). There is no need to compute the angle between these vectors. There is a much easier way to do this. What is another way to compute the inner product that |a||b|cos(theta)? How would you generalize this to complex numbers?

And finally, what is in your class notes and text? I am quite certain your instructor does not expect you to derive the formula for computing the inner product in C3. He or she expects you to use something you have already been taught.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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