Easy -1.8 This is a direct recall question testing the fundamental Pythagorean identity cos²x + sin²x = 1, requiring only simple rearrangement to cos²x = 1 - sin²x. It's a 1-mark multiple choice question with no calculation or problem-solving needed, making it significantly easier than average A-level questions.
One of the equations below is true for all values of \(x\)
Identify the correct equation.
Tick (\(\checkmark\)) one box.
[1 mark]
\(\cos^2 x = -1 - \sin^2 x\) \(\square\)
\(\cos^2 x = -1 + \sin^2 x\) \(\square\)
\(\cos^2 x = 1 - \sin^2 x\) \(\square\)
\(\cos^2 x = 1 + \sin^2 x\) \(\square\)
One of the equations below is true for all values of $x$
Identify the correct equation.
Tick ($\checkmark$) one box.
[1 mark]
$\cos^2 x = -1 - \sin^2 x$ $\square$
$\cos^2 x = -1 + \sin^2 x$ $\square$
$\cos^2 x = 1 - \sin^2 x$ $\square$
$\cos^2 x = 1 + \sin^2 x$ $\square$
\hfill \mbox{\textit{AQA AS Paper 2 2024 Q2 [1]}}