Question 1 10 points a) Roots of a complex number lie on the vertices of a square of arm length 22. The diagonals intersect at the origin, and make an angle with the axes. Find the complex number. b) Using 1+2++ + 2" m obtain the Lagrange's identity 1 + cos 0 + cos(20)+. + cos(no) 1-2+1 1-z = + sin [(2n + 1)] 2 sin (1) (2)