# How do you use the amplitude and period to graph f(x) = 3 Sin x + 4 Cos x?

Feb 10, 2016

$A = \sqrt{{3}^{2} + {4}^{2}} = 5$
The zero is obtained by solving $f \left(x\right) = 0$
Note the period is $2 \pi$
$4 \cos x = - 3 \sin x$;
$\tan x = - \frac{4}{3}$; ${\tan}^{-} 1 \left(- \frac{4}{3}\right) = x \approx - .93$