Please help with these questions.

6. Verify the Cauchy-Schwarz inequality and the triangle inequality for the vectors i = (1, -1, 1, -1, 1) and y = (3, 0, 0, 0, 2). 7. Given i E R" and y E R". Prove that: 21212 + 2 712 = 12+912+12-912; 8. Let u, J E R". If u = 7 , show that u + U and u - U are orthogonal