Please fast 7 . I f 1 + x n = ∑ r = 0 n C r X r , 1 + C 1 C 0 1 + C 2 C 1 . . . . . . . . 1 + C n C n - 1 i s e q u a l t o a n n - 1 n - 1 ! ( b ) n + 1 n - 1 n - 1 ! ( c ) n + 1 n n ! ( d ) n + 1 n + 1 n ! Share with your friends Share 0 Shruti Tyagi answered this Dear Student, 1+C1C01+C2C11+C3C2...1+CnCn-1Now calculating CrCr-1=n!r!×n-r!n!r-1!×n-r+1!=n!r!×n-r!×r-1!×n-r+1!n!=r-1!×n-r+1n-r!rr-1!×n-r!=n-r+1rHence 1+CrCr-1=1+n-r+1r=r+n-r+1r=n+1rHence we get 1+C1C01+C2C11+C3C2...1+CnCn-1=n+11×n+12×n+13....×n+1n⇒n+1n1×2×3×4...×n⇒n+1nn!option C is correct Regards, 0 View Full Answer