x7 in ( 1 + x ) 11 Solution i thought the statement that is abasic one and gave the proof any how the proof is we can write (1+x)n as (1+x)*(1+x)*(1+x).....up to ntimes we have to find the coefficient of xr we have toselect r XS from n X so the number ways it can be done is nCr so it is done I mean to say we will have xr+xr+....nCR times now we have to find the coefficient of x7 in theexpansion of (1+x)11 =11C7.

1. x7 in ( 1 + x ) 11
Solution
i thought the statement that is abasic one and gave the proof any how the proof is
we can write (1+x)n as (1+x)*(1+x)*(1+x).....up to ntimes we have to find the coefficient of xr
we have toselect r XS from n X so the number ways it can be done is nCr so it is done I mean to
say we will have xr+xr+....nCR times now we have to find the coefficient of x7 in theexpansion
of (1+x)11 =11C7