Question

The maximum height of the curve
$y=6\cos x-8\sin x$ above the X - axis is

• A. 6
• B. 8
• C. 14
• D. 10

Answer 1

The correct option is D 10

$y=10(\frac{6}{10}\cos x-\frac{8}{10}\sin x)$
$=10\left(\cos \right(x+\theta \left)\right)$
$\tan \theta =\frac{8}{6}$
$y_{max}=10$