Question 1*For \(\frac{4x+1}{(x-2)(x+5)}=\frac{A}{x-2}+\frac{B}{x+5}\), what value of \(x\) finds \(A\) by cover-up?
Question 11***+Explain why cover-up is not directly valid for \(\frac{x+1}{(x-2)^2}\), then decompose it by another method.
Question 12***+Use cover-up to evaluate \(\int \frac{x+5}{(x+1)(x+4)}\,dx\), and check the numerator after decomposing.
Question 15****+Find \(k\) so that the \(\frac{1}{x-2}\) term vanishes in the decomposition of \(\frac{kx+1}{(x-2)(x+3)}\).
Question 16****+For \(\frac{x+a}{(x-1)(x+1)}\), find \(a\) so the cover-up coefficients are opposites.
Question 17****+For \(\frac{x+a}{(x-2)(x+2)}\), find \(a\) so the two cover-up coefficients are equal.
Question 18*****A student uses cover-up on \(\frac{x+1}{(x-1)(x^2+4)}\) and writes \(\frac{A}{x-1}+\frac{B}{x^2+4}\). Diagnose the issue.
Question 19*****Justify the cover-up formula for \(A\) in \(\frac{P(x)}{(x-a)(x-b)}=\frac{A}{x-a}+\frac{B}{x-b}\), where \(a\ne b\).
Question 20*****Use cover-up where valid to evaluate \(\int \frac{2x^2+x-1}{(x-2)(x+1)(x-1)}\,dx\), and explain the zero coefficient if it occurs.