How do you find the value of cotθ if cosθ = -4/5? Trigonometry Right Triangles Relating Trigonometric Functions 1 Answer Nghi N. May 19, 2015 First, find sin x. #sin^2 x = 1 - cos^2 x = 1 - 16/25 = 9/25 -> sin x = +-3/5# #cos x = -4/5#, then x is in Quadrant II, sin x is positive# (3/5)# #cot x = cos x /sin x = (-4/5):(3/5) = -4/3# 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 12406 views around the world You can reuse this answer Creative Commons License