Binomial TheoremHard
Question
If the coefficients of the three successive terms in the binomial expansion of (1 + x)n are in the ratio 1 : 7 : 42, then the first of these terms in the expansion is
Options
A.6th
B.7th
C.8th
D.9th
Solution
nCr-1 : nCr : nCr+1
⇒ 8r = n + 1
⇒ 7r = n − 6
⇒ r = 7
⇒ 8r = n + 1
⇒ 7r = n − 6
⇒ r = 7
Create a free account to view solution
View Solution FreeMore Binomial Theorem Questions
If (1 + x)n = C0 + C1x + C2x2 + ...Cn. xn then the value of C0 + 3C1 + 5C2 + .....+ (2n + 1) Cn is-...If Cr stands for nCr, then the sum of the series [Co2 - 2C12 + 3C22 - .... + (- 1)r (n + 1)Cn2] where n is an even posit...The value of is equal to...If (1 + x + x2 + x3)5 = a0 + a1x + a2x2 +....................... + a15x15, then a10 equals to :If (1 + x + x2 + x3)5 = a...If (1 + by)n = (1 + 8y + 24 y2 + ....) then the value of b and n are respectively-...