Hey! I need some help with this task:
Suppose that u1,u2 is an orthonormal basis of R2, that means u1*u2=0 and ui*ui=1, i=1,2.
Let y=[<y1,y2>] be a vector in R2 and v = y1u1 + y2u2. Show that the vectors y and v are equal in length.
The v vector is a sum of two scalar products. I don't...