Question:
x-(1/x) = 8 ആയാൽ x³-(1/x³) ന്റെ വില എത്ര?
A536
B342
C456
D356
Answer:
A. 536
Explanation:
x-(1/x) = 8 ------------ (1) (A -B)³ = A³ - B³ - 3AB(A - B) ആണ്. ഇവിടെ A= x, B= 1/x എന്ന് എടുത്താൽ (x-1/x)³ = x³ - (1/x)³ -3x × (1/x) × (x -1/x) = x³ -(1/x)³ - 3(x-1/x) x³ -(1/x)³ = (x-1/x)³ + 3(x-1/x) = 8³ + 3 × 8 = 512 + 24 = 536