Question

Given tan(8) = 4/3 and sin(8) = -4/5, find cos(8).

A. 1/3
B. -1/3
C. 3/5
D.-3/5
E. -3squared/5

Answer 1

I assume you mean β in place of 8.

Remember that tangent is defined as

tan(β) = sin(β) / cos(β)

so that

cos(β) = sin(β) / tan(β) = (-4/5) / (4/3) = -3/5 … … … [D]