AP EAMCET202418 May 2024Morning ShiftMathematicsBinomial TheoremActual
The absolute value of the difference of the coefficients of x^4 and x^6 in the expansion of 2 x^2 (x^2+1 ) (x^2+2 ) is
Options
- A13 4
- B1 4
- C9 4
- D1
Correct answer
A. 13 4
Step-by-step solution
Since 2 x^2 (x^2+1 ) (x^2+2 ) = -2 x^2+1 + 4 x^2+2 =-2 (1+x^2 )⁻¹+ 4 2 (1+ x^2 2 )⁻¹=-2 (1+x^2 )⁻¹+2 (1+ x^2 2 )⁻¹=-2 (1-x^2+x^4-x^6+ . )+2 (1- x^2 2 + x^4 4 - x^6 8 + . ) So, co-efficient of x^4=-2+ 1 2 = -3 2 and co-efficient of x^6=2- 1 4 = 7 4 Now, required value = 7 4 + 3 2 = 13 4