7.5 Writing sums of trig functions as a single trig function
Express in the form .
Solution: start by applying the angle addition formula for (Equation 7.8).
From here, comparing coefficients gives
as well as that
So the solution is
Note that this technique is very useful for solving equations of the form , as we just rewrite the left hand side as a single trigonometric function, and then use the method for solving such trig functions66 6 Explored in the section above..