I’m failing my geometry class, if you know geometry please help me

Question

1) In right triangle ABC, with right angle A, let sin C = m and cos C = n. Using this relationship, find cos B – sin B. Show

your work and explain your reasoning.

2) Sandy says that the tangent for an angle of 0° has a value of 0 because the opposite side of the triangle has a length of 0. What does she mean?

Answer 1

For the first question - In a right triangle like the one that you described, sin(C) = cos(B) and sin(B) = cos(C). Draw a picture to prove this to yourself.

Thus, cos(B) - sin(B) = sin(C) - cos(C) = m - n.