## Equation of A+Bsinx or A+Bcos x From a Graph

Given a graph of the form
$y=A+B cos x, \: A+B sin x$
, shown below,

We can easily find
$A$
and
$B$

$A=\frac{y_{MAX}+y_{MIN}}{2}=\frac{7+3}{2}=5$

$A=\frac{y_{MAX}-y_{MIN}}{2}=\frac{7-3}{2}=2$

The equation of the graph is
$y=5+2 cos x$