AP EAMCET202317 May 2023Evening ShiftMathematicsBinomial TheoremActual
The coefficient of x^2 in the expansion of (1-3 x)^ 1 3 (1+2 x)^ - 1 2 is
Options
- A- 3 2
- B3 2
- C1 2
- D- 1 2
Correct answer
B. 3 2
Step-by-step solution
(1-3 x)^ 1 3 (1+2 x)^ - 1 2 aligned & = (1+ 1 3 (-3 x)+ 1 3 ( 1 3 -1 ) 2 ! (-3 x)^2+ ) & . 1+ (- 1 2 )(2 x)+ (- 1 2 ) (- 1 2 -1 ) 2 ! (2 x)^2+ ) & = (1-x-x^2+ ) (1-x+ 3 2 x^2+ ) aligned The coefficient of x^2=1 3 2 +(-1) (-1)+1 (-1)= 3 2 +1-1= 3 2