Question #142e0 Trigonometry Right Triangles Relating Trigonometric Functions 1 Answer Ratnesh Bhosale Mar 8, 2017 #rArr costheta = 5/sqrt61# Explanation: #tan theta= -6/5# Using the identity in trigonometry, #1 + tan^2 theta= sec^2theta# #rArr 1+36/25= sec^2theta# #rArr 61/25= sec^2theta# #rArr sectheta = sqrt61/5# Also, #cos theta= 1/sec theta# #rArr costheta = 5/sqrt61# 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