If the coefficient of $x^7$ in $\left(ax-\frac{1}{bx^2}\right)^{13}$ and the coefficient of $x^{-5}$ in $\left(ax+\frac{1}{bx^2}\right)^{13}$ are equal, then $a^4b^4$ is equal to:

JEE Main 2023 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 10 April 2023, Shift 1, Maths Q5

Question 5 of 90 in this shift, Maths question 5 of 30, Section A.

If the coefficient of

x^7

\left(ax-\frac{1}{bx^2}\right)^{13}

and the coefficient of

x^{-5}

\left(ax+\frac{1}{bx^2}\right)^{13}

are equal, then

a^4b^4

is equal to:

Official answer

Option 2

NTA final key.