How do you find the exact values of #costheta# and #tantheta# when #sintheta=1/2#? Trigonometry Right Triangles Relating Trigonometric Functions 1 Answer Gerardina C. Jan 7, 2017 #costheta=+-sqrt(3)/2# #tantheta=+-sqrt(3)/3# Explanation: Since #costheta=+-sqrt(1-sin^2theta)# you get #costheta=+-sqrt(1-1/4)=+-sqrt(3)/2# Since #tantheta=sintheta/costheta#, you get #tantheta=(1/cancel2)/(+-sqrt(3)/cancel2)# The #tantheta=+-1/sqrt(3)=+-sqrt(3)/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 1740 views around the world You can reuse this answer Creative Commons License