Question #33ab5 Trigonometry Right Triangles Relating Trigonometric Functions 1 Answer P dilip_k Dec 20, 2016 #RHS=sin7theta+sin4theta-sin2theta+sintheta# #=(sin7theta+sintheta)+(sin4theta-sin2theta)# #=(2sin4thetacos3theta)+(2cos3thetasintheta)# #=2(sin4theta+sintheta)cos3theta# #=4sin((5theta)/2)cos((3theta)/2)cos3theta=LHS# Proved Answer link Related questions What does it mean to find the sign of a trigonometric function and how do you find it? What are the reciprocal identities of trigonometric functions? What are the quotient identities for a trigonometric functions? What are the cofunction identities and reflection properties for trigonometric functions? What is the pythagorean identity? If #sec theta = 4#, how do you use the reciprocal identity to find #cos theta#? How do you find the domain and range of sine, cosine, and tangent? What quadrant does #cot 325^@# lie in and what is the sign? How do you use use quotient identities to explain why the tangent and cotangent function have... How do you show that #1+tan^2 theta = sec ^2 theta#? See all questions in Relating Trigonometric Functions Impact of this question 1500 views around the world You can reuse this answer Creative Commons License