Official papers

Official 2020 Paper 2 · Q18

Paper 2Logic & proof

In this question, f(x)=ax3+bx2+cx+df(x)=ax^3+bx^2+cx+d and g(x)=px3+qx2+rx+sg(x)=px^3+qx^2+rx+s are cubic polynomials.

If f(x)−g(x)>0f(x)-g(x)>0 for every real xx, which of the following is/are necessarily true?

  • I a>pa>p
  • II if b=qb=q then c=rc=r
  • III d>sd>s
Anone of them
BI only
CII only
DIII only
EI and II only
FI and III only
GII and III only
HI, II and III

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