First slide

Binomial theorem for positive integral Index

Question

If $A$ and $B$ are coefficients of $x^{r}$ and $x^{n - r}$ respectively in the expansion of $(1 + x)^{n}$ , then

Moderate

A

$A = B$
B

$A + B = 0$
C

$A = r B$
D

$A = n B$

Solution

We have,
A = Coeff. of $x^{r}$ in the expansion of $(1 + x)^{n} =^{n} C_{r}$
B = Coeff. of $x^{n - r}$ in the expansion of $(1 + x)^{n} =^{n} C_{n - r}$
$∵^{n} C_{r} =^{n} C_{n - r} ∴ A = B$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App