99 Percentile Qs Bank for JEE MainMathematicsBinomial Theorem
If ( (1-x+x^2 )¹⁰=a₀+a₁ x+a₂ x^2+ +a₂₀ x²⁰ ), then (2 a₂+3 a₃+4 a₄+ +20 a₂₀= )
Options
- A0
- B10
- C20
- D-20
Correct answer
C. 20
Step-by-step solution
( (1-x+x^2 )¹⁰=a₀+a₁ x+a₂ x^2+ +a₂₀ x²⁰ ) On differentiating ( aligned & 10 (1-x+x^2 )^9 (-1+2 x)=a₁+2 a₂ x+3 a₃ x^2 & + +20 a₂₀ x¹⁹ aligned ) At (x=1 ) ( a₁+2 a₂+3 a₃+ +20 a₂₀=10 ) At (x=0 a₁=-10 ) So, (2 a₂+3 a₃+ +20 a₂₀=20 )