Which of the following is a Double Angle Identity formula?
A)Sin 2x = 2 sin xcosx
B)Sin (x + y) = sin xcosy - cosx sin y
C)Sin xcosy = ½ [sin(x + y) + sin (x - y)
D)All of the above

Question

Quizplus · Accepted Answer

Sin 2x = 2 sin xcosx is a Double Angle Identity formula.
Double Angle formulas are useful when integrating rational functions of sine and cosine.
Sin (x + y) = sin xcosy - cosx sin y is a Sum and Difference Identity formula
Sin xcosy = ½ [sin(x + y) + sin (x - y) is a Product-Sum Identity formula

Which of the Following Is a Double Angle Identity Formula