Question 2*In polynomial division, what condition must the remainder \(R(x)\) satisfy when dividing by \(Q(x)\)?
Question 12***+A student writes \(\frac{x^3-1}{x-1}=x^2+1\). Explain the error and give the correct quotient.
Question 15****+Find \(a\) so that dividing \(x^3+ax+4\) by \(x-2\) leaves remainder \(0\), then write the quotient.
Question 16****+Find \(k\) so that \(\frac{x^3+kx+1}{x^2+1}\) has remainder \(1\) after division, then integrate the rational function.
Question 18*****A student divides \(x^4+2x^2+3\) by \(x^2+1\) and stops at \(x^2+2\) with remainder \(3\). Diagnose the error and give the correct decomposition.
Question 19*****Prove that if \(\deg P\ge \deg Q\) and \(Q\ne0\), polynomial division writes \(\frac{P(x)}{Q(x)}=S(x)+\frac{R(x)}{Q(x)}\) with \(\deg R<\deg Q\).
Question 20*****Evaluate \(\int \frac{x^5-x^4+x^2+1}{x^2+1}\,dx\), showing the division and the remaining standard integrals.