Use proof by contradiction to show that for all x∈Rx \in \mathbb{R}x∈R
x4+100≥20x2 x^4 + 100 \ge 20x^2 x4+100≥20x2Show that the following statement is not true.
"The sum of three consecutive even integers is always a multiple of 12."
107 exam-style questions on Edexcel A Level Maths 1.1 Proof by Contradiction. Each one has a worked solution and a mark scheme showing where the marks go.