Question

(x/a-a/x)¹¹ coefficient of x power 7​

Answer 1

We could observe x/a and a/x are inverses. (x/a × a/x = 1)

Now, if we lower the power by 2

→ (x/a-a/x)² × (x/a-a/x)² × ... × (x/a-a/x)

→ (x²/a²-2+a²/x²) × (x²/a²-2+a²/x²) × ... × (x/a-a/x)

report this answer please, I didn't consider x²/a² × a²/x²

Only the last bracket has x/a.

Coefficient of x :

→ (-2) × (-2) × ... × 1/a

→ (-2)⁵ × 1/a

→ -128/a

Therefore, the coefficient of x is -128/a