JEE Main202312 Apr 2023Morning ShiftMathematicsBinomial TheoremActual
The sum, of the coefficients of the first 50 terms in the binomial expansion of 1 - x 100 , is equal to
Options
- A101 C 50
- B99 C 49
- C- 101 C 50
- D- 99 C 49
Correct answer
D. - 99 C 49
Step-by-step solution
We know that 1 - x 100 = C 0 100 - C 1 100 · x + C 2 100 · x 2 - . . . . . . . - C 49 100 · x 49 + . . . . . . . + C 100 100 · x 100 Now let, the sum of first fifty coefficients be S . ⇒ S = C 0 100 - C 1 100 + C 2 100 - . . . . . . . - C 49 100 Let us substitute x = 1 in the expansion. ⇒ 1 - 1 100 = C 0 100 - C 1 100 · 1 + C 2 100 · 1 2 - . . . . . . . - C 49 100 · 1 49 + . . . . . . . + C 100 100 · 1 100 ⇒ 0 = C 0 100 - C 1 100 + C 2 100 - . . . . . . . -