1.

Find the term independent of x in  \((3x - \frac{2}{x^2})^{15}\)

Answer»

\((3x - \frac{2}{x^2})^{15}\)

Here x → 3x a → \(\frac{-2}{x^2}\) and n =15 

Tr+1 = 15Cr.(3x)15-r . (\(\frac{-2}{x^2}\))r

= 15Cr.315-r .(-2)r . x15-r 

We have x15-3r. = x0 ⇒ 15 = 3r ⇒ r = 5 

T = 15C5.315-5 .(-2)5 = -15C5 .310 25 

∴ The term independent of x is -15C5.310.25


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