(i) To find the first three terms in the expansion of \((1 + x)^5\), we use the binomial theorem:
\((1 + x)^5 = \sum_{k=0}^{5} \binom{5}{k} x^k\)
The first three terms are:
\(\binom{5}{0} x^0 = 1\)
\(\binom{5}{1} x^1 = 5x\)
\(\binom{5}{2} x^2 = 10x^2\)
Thus, the first three terms are \(1 + 5x + 10x^2\).
(ii) For the expansion of \((1 + (px + x^2))^5\), we replace \(x\) by \((px + x^2)\) in the expansion of \((1 + x)^5\):
\((1 + (px + x^2))^5 = 1 + 5(px + x^2) + 10(px + x^2)^2\)
We need the coefficient of \(x^2\):
From \(5(px + x^2)\), the \(x^2\) term is \(5x^2\).
From \(10(px + x^2)^2\), the \(x^2\) term is \(10p^2x^2\).
Thus, the coefficient of \(x^2\) is \(5 + 10p^2\).
We are given that this coefficient is 95:
\(5 + 10p^2 = 95\)
\(10p^2 = 90\)
\(p^2 = 9\)
\(p = 3\) (since \(p\) is positive)