Extracted text: Let S 3D {u1, и2, из, ид} С R, where U1 = : (1,1, 1, 1), и2 %3D (1,1, —1, —1), из 3D (1,—1,1, -1), и4 3 (1, —1, —1, 1). (a) Show that S is orthogonal and is a basis for R4. (b) Write v = (1, 3, –5, 6) as a linear combination of u1, u2, U3, U4. (c) Find the coordinates of an arbitrary vector v = (a,b, c, d) in Rª relative to the basis S. (d) Normalize S to obtain an orthonormal basis for R4.