IIT JEE , AIEEE Forum - Mathematics , Algebra

sachin_gupta1991

Q.1. Prove that For any 1<=r<=n-1, the value of ⁿC_r- 2 ⁿC_r-1+ 3 ⁿC_r-2...........(-1)^r(r+1) is equal to ^n-2C_r.

Q.2. The coefficient of xⁿ in (1+x+2x²+3x³+.........nxⁿ) is

Q.3. 53⁵³ - 33³³is divisible by a)91 b)92 c)90 d)93

SALUTES ASSURED TO ALL CORRECT ANSWERS TO ANY OF THE QUESTIONS.

ramyani

Q.2. The coefficient of xⁿ in (1+x+2x²+3x³+.........nxⁿ) is

Is it nxⁿ or nx^n-1 ?

pardesi

for 3 it's b

sachin_gupta1991

No. For 3,the correct answer is C, not B.

pardesi

that is impossible since 3 divides 90 and 3 divides 33 but not 53 so 3 cant divide 53^{33}-33^{33}

Asmita

hey........... is d answr 2 d 2nd 1 "n"..............