Most Important Selected Qs for JEE AdvancedMathematicsBinomial Theorem
The sum of the coefficients of even power of x in the expansion of (1+x+x^2+x^3 )^5 is
Options
- A256
- B128
- C512
- D64
Correct answer
C. 512
Step-by-step solution
(1+x+x^2+x^3 )^5=a₀+a₁ x+a₂ x^2+a₃ x^3+a₄ x^4+ . .+a₁₅ x¹⁵ Put x=1 and x=-1 and add aligned & 4^5=a₀+a₁+a₂+a₃+a₄+ . .+a¹⁵ & 0=a₀-a₁+a₂-a₃+a₄- . .-a¹⁵ aligned aligned & 4^5=2 (a₀+a₂+a₄+ +a₁₄ ) & a₀+a₂+a₄+ +a₁₄=512 aligned