Question

tan（75°-α）-sin（α+15°）需过程

Answer 1

tan(75º-α)-sin(α+15º)=-tan(α-75º)-sin(α-75º+90º)=-[tan(α-75º)+sin(α-75º+90º)]=-[tan(α-75º)+cos(α-75º)]=-[sin(α-75º)/cos(α-75º)+cos(α-75º)]=-[1+sin(α-75º)-sin²(α-75º)]/cos(α-75º)