1.1.3 Proof by contradiction (A-level only)

The voltage $V$ in an electrical circuit is modeled by the function

\frac{1}{9}t^9 + 2\cos t

for $\in \mathbb{R}$ , where $t$ is the time in seconds. Use proof by contradiction to prove that the voltage function has no stationary points.

[5]

1.1.3 Proof by contradiction (A-level only) Questions

The voltage $V$ in an electrical circuit is modeled by the function

\frac{1}{9}t^9 + 2\cos t

for $\in \mathbb{R}$ , where $t$ is the time in seconds. Use proof by contradiction to prove that the voltage function has no stationary points.

[5]