By considering the general term in the expansion of $\left(x^5 + \frac{1}{x}\right)^7$, explain wh

Question

By considering the general term in the expansion of $\left(x^5 + \frac{1}{x}\right)^7$, explain why there are no even powers of $x$ in its expansion.[2] Given that the coefficient of $x^6$ in the expansion of $\left(x^5 + \frac{1}{x}\right)^7 + (kx + 3)^7$ is $1344$, where $k$ is a positive constant, find the coefficient of $x^4$ in the expansion.[4]

Accepted Answer

(i) There are no even powers of $x$. (ii) $15120$

(A Math) 2025 CCHY PRELIMS P1 Q5

(A Math) 2025 CCHY PRELIMS P1 Q5

Solution:

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