Use the information given below to find cos (α-β)

Question

Use the information given below to find cos (α-β)

tan(α) = 3/4, with α in quadrant I

sin(β) = 3/5, with β in quadrant II

Give the exact answer, not a decimal approximation.

please help and explain how you got your answer, too.

Answer 1

I solved one of these a few minutes ago for you. Use the same process as that.

The angle subtraction equation is:

cos(α – β) = cos(α)cos(β) + sin(α)sin(β)

With the information given, tan(α) = 3/4, with α in quadrant I and sin(β) = 3/5, with β in quadrant II

1) Draw the associated triangles and determine from those what the values are for cos(α), cos(β), and sin(α)

2) Put those values into the equation to find cos(α – β)