Question

Let cos^-1(x) + cos^-1(2x) + cos^-1(3x) = π If x satisfies the cubic equation ax³ + bx² + cx + d = 0, then find the value of (b + c) - (a + d)

Answer 1

Given, cos^-1(x) + cos^-1(2x) + cos^-1(3x) = π

Thus, a = 12, b = 14, c = 0, d = - 1

Hence, the value of (b + c) - (a + d)

= 14 - 11 = 3.