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QJEEM19Ma32a7: JEE Main 2019 Mathematics - Class 11 JEEM19Ma32a7 Solution: The coefficient of x 18 in the product (1 + x) (1 – x) 10 (1 +…
The coefficient of x18 in the product
(1 + x) (1 – x)10 (1 + x + x2)9 is :
(1 + x) (1 – x)10 (1 + x + x2)9 is :
Multiple Choice Options
- A 126
- B -84
- C -126
- D 84
Step-by-Step Verified Solution
Coefficient of x18 in (1 + x) (1 - x)10 (1 + x + x2)9
Coefficient of x18 in {(1 - x) (1 - x2) (1 + x + x2)}9
Coefficient of x18 in (1 - x2) (1 - x3)9
9C6 - 0 = 84
Coefficient of x18 in {(1 - x) (1 - x2) (1 + x + x2)}9
Coefficient of x18 in (1 - x2) (1 - x3)9
9C6 - 0 = 84