Binomial TheoremHard
Question
The sum of coefficients of integral powers of x in the binomial expansion of (1 − 2√x)50 is :
Options
A.1/2 (350 − 1)
B.1/2 (250 + 1)
C.1/2 (350 + 1)
D.1/2 (350)
Solution
∵ (1 − 2 √x)50 = 50C0 − 50C1 (2√x) + 50C2 (2√x)2 +.....+ 50C50 (2√x)50
∴ consider (1 + 2√x)50 = 50C0 + 50C1 (2√x)50 +.......+ 50C50 (2√x)50
add both equations and put x = 1
⇒ sum of coefficients of integral powers of
x =
(1 + 350)
∴ consider (1 + 2√x)50 = 50C0 + 50C1 (2√x)50 +.......+ 50C50 (2√x)50
add both equations and put x = 1
⇒ sum of coefficients of integral powers of
x =
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