Posted by Jaime on .
given that sec theta = radical13/whole number 3, and csctheta<0 find sin theta using the 2different methods;
1)using the "xyr" definition
2) using identities only

Geometryy 
Ms. Sue,
Timmy, Ryland, Cobra, Jaime  you must be having an identity crisis tonight.
Please use the same name for all of your posts. 
Geometryy 
Reiny,
given sec Ø = √13/3 > cosØ = 3/√13
also cscØ < 0 > sinØ < 0
Ø must be in quadr IV
so x = 3 , r = √13
x^2 + y^2 = r^2
9 + y^2 = 13
y^2 = 4
y = ± 2 , but in IV y = 2
sin Ø = 2/√13
2) you should know that
sin^2Ø + cos^2Ø = 1
sin^2Ø + 9/13 = 1
sin^2Ø = 4/13
sinØ = 2/√13 , but we know that Ø is in IV, where the sine is negative, so
sinØ = 2/√13