NTA Abhyas JEE Main2020MathematicsBinomial TheoremPractice
The coefficient of x 4 in the expansion 1 - x 8 1 + x 12 is equal to
Options
- A1
- B- 48
- C28
- D- 19
Correct answer
D. - 19
Step-by-step solution
1 - x 8 1 + x 12 = 1 - x 2 8 1 + x 4 = 1 - 8 x 2 + 28 x 4 … . 1 + 4 x + 6 x 2 + 4 x 3 + x 4 Coefficient of x 4 = 1 - 48 + 28 = - 19