JEE Main20238 Apr 2023Morning ShiftMathematicsBinomial TheoremActual
Let t denote the greatest integer ≤ t . if the constant term in the expansion of 3 x 2 - 1 2 x 5 7 is α then α is equal to _ _ _ _ _
Correct answer
0
Step-by-step solution
The given expansion is 3 x 2 - 1 2 x 5 7 . The general term in the binomial expansion of x + a n is given by T r + 1 = C r n x n - r a r . ⇒ T r + 1 = C r 7 3 x 2 7 - r - 1 2 x 5 r = C r 7 - 1 r 3 7 - r 2 r x 14 - 2 r - 5 r Now for term independent of x ⇒ 14 - 2 r - 5 r = 0 ⇒ r = 2 Coefficient of x 0 is C 2 7 - 1 2 × 3 7 - 2 2 2 = 7 × 6 2 × 3 5 2 2 . ⇒ α = 5103 4 ⇒ α = 1275 Hence this is the required answer.