4x - 1 A B C ------- = --- + ---------- + -------- x^3 - 4x x x - 2 x + 2
4x - 1 = A(x - 2)(x + 2) + Bx(x + 2) + Cx(x - 2)
Let x = 2 then 4(2) - 1 = B(2)(2+2) so 7 = 8B and B = 7/8 Let x = -2 then -8 - 1 = C-2)(-2-2) so -9 = 8C and C = -9/8 Let x = 0 then -1 = -4A and A = 1/4