Discrete Math Quiz
20 questions · no time limit
0:00
LOGIC AND PROOF
Question 1 of 20
No time limit
Current
Answered
Flagged
Not seen
A student attempts to prove by contrapositive that "If f(x)=x3+2xf(x) = x^3 + 2x, then ff is one-to-one." The student writes: "Assume ff is not one-to-one. Then there exist a≠ba \neq b such that f(a)=f(b)f(a) = f(b). This means a3+2a=b3+2ba^3 + 2a = b^3 + 2b, so a3−b3=2b−2a=2(b−a)a^3 - b^3 = 2b - 2a = 2(b - a)." What should the student do next to complete the proof?
YOUR PROGRESS
20
QUESTIONS
Ready when you are
Answer in any order. Your progress shows here as you go.
QUESTIONS
KEYBOARD
Pick an answer ABCD
Next question ↵→
Previous ←
Flag for review F
Answers save as you go · flagged questions come back at the end