JEE Main20248 Apr 2024Evening ShiftMathematicsBinomial TheoremActual
If the term independent of x in the expansion of ( a x^2+ 1 2 x^3 )¹⁰ is 105 , then a ^2 is equal to :
Options
- A2
- B4
- C6
- D9
Correct answer
B. 4
Step-by-step solution
( a x ^2+ 1 2 x ^3 )¹⁰ General term = ¹⁰ C _ r ( a x ^2 )^ 10- r ( 1 2 x ^3 )^ r aligned & 20-2 r-3 r=0 & r =4 & ¹⁰ C ₄ a ^3 1 16 =105 & a ^3=8 & a ^2=4 aligned SECTION - B