Question -
Answer -
Given:
(3x – 1/x2)10
The 5th termfrom the end is the (11 – 5 + 1)th, is., 7th term from thebeginning.
So,
T7 = T6+1
= 10C6 (3x)10-6 (-1/x2)6
= 10C6 (3)4 (x)4 (1/x12)
= [10×9×8×7×81] /[4×3×2×x8]
= 17010 / x8
∴ The 5th termof the expression (3x – 1/x2)10 is 17010 / x8.