MEDIUM
JEE Main/Advance
IMPORTANT
Earn 100

If the coefficient of xn in the expansion of 1-9x+20x2-1 is an+1-bn+1 (where a, b are coprime) then ab is equal to (a>b).

Important Questions on Binomial Theorem

MEDIUM
JEE Main/Advance
IMPORTANT
The coefficient of x9 in the expansion of r=11001+xr is equal to
MEDIUM
JEE Main/Advance
IMPORTANT
If 1-x3n=r=0narxr(1-x)3n-2r,x0 then the value of ar where nN is
HARD
JEE Main/Advance
IMPORTANT
Let 1+x221+xn=k=0n+4ak·xk, If a1,a2 and a3 are in A.P., then the value of n is
HARD
JEE Main/Advance
IMPORTANT
r=0n-1r·Crn12r+3r22r+7r23r+15r24r+m terms =
MEDIUM
JEE Main/Advance
IMPORTANT
In the expansion of (x+a)n, the sum of even terms is E, the sum of odd terms is O, then O2-E2 is equal to
HARD
JEE Main/Advance
IMPORTANT
For 4rn
nr+4nr+1+6nr+2+4nr+3+nr+4 equals
HARD
JEE Main/Advance
IMPORTANT
If x+y=1, then r=0nr2Crnxryn-r equals
MEDIUM
JEE Main/Advance
IMPORTANT
The value of C0+C1C1+C2.Cn-1+Cn is