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Thesum of coefficients of integral powers of x in the binomial expansion of `(1-2sqrt(x))^(50)`is:(1) `1/2(3^(50)+1)`(2) `1/2(3^(50))`(3) `1/2(3^(50)-1)`(4) `1/2(2^(50)+1)` |
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Answer» `(1- 2 sqrtx)^50 = .^50c_0 - .^50c_1 (2 sqrtx)^1 + .^50c_2(2 sqrtx)^2- .^50c_3(2 sqrtx)^3 + .^50c_4 (2sqrtx)4 .....` `s= .^50c_0 + .^50c_2 *2^2 + .^50 c_4 (2)^4 + .... + .^50c_502^50` `(1+x)^50 = 1+ .^50C_1x^1 + .^50c_2x^2+...` `x=2,-2` `(1+2)^50 = 1 +.^50c_1 (2) + .^50c_2(2)^2 + ..` `(1-2)^50 = 1- .^50c_1(2) + .^50c_2(2)^2 - .^50C_3(2)^3+ .....` now,`3^50 + 1 = 2[.^50C_0 + .^50c_2 (2)^2 + .^50c_4(2)^4+ ..]` `(3^50 +1)/2 = .^50C_0 + .^50c_2(2) + .^50c_4 (2)^4+...` so, option 4 is correct answer |
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