# Get the vector Norm without absolute values? [duplicate]

I want to get the Norm of a vector which involves sines and cosines (So I really need to replace it by the Pythagorean theorem). Since I know that all my results are going to be real and positive I don't care about the Abs before squaring the terms.

How can I get $$\sqrt{ r_x ^ 2 + r_y ^ 2 + r_z ^ 2 }$$

Instead of: $$\sqrt{ |r_x| ^ 2 + |r_y| ^ 2 + |r_z| ^ 2 }$$

## marked as duplicate by Michael E2, C. E., Bob Hanlon, J. M. will be back soon♦Apr 17 '17 at 4:02

• Sqrt[vec.vec] where vec is your vector. . in Mathematica is the dot product. – C. E. Apr 16 '17 at 19:34
• Norm[vec] // ComplexExpand – Bob Hanlon Apr 16 '17 at 21:54
Sqrt[vec.vec]

where vec is your vector.