Official papers

Official 2021 Paper 2 · Q9

Paper 2Logic & proofAlgebra

Consider the following statements about a polynomial f(x)f(x):

  • I. f(x)=px3+qx2+rx+sf(x)=px^3+qx^2+rx+s, where p≠0p\ne0.
  • II. There is a real number tt for which f′(t)=0f'(t)=0.
  • III. There are real numbers uu and vv for which f(u)f(v)<0f(u)f(v)<0.

Which of these statements is/are sufficient for the equation f(x)=0f(x)=0 to have a real solution?

Statement I is
sufficient
Statement II is
sufficient
Statement III is
sufficient
A Yes Yes Yes
B Yes Yes No
C Yes No Yes
D Yes No No
E No Yes Yes
F No Yes No
G No No Yes
H No No No
ABCDEFGH

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