Second,be carefulabouthow you pronouncethe namesof the functions.Whenwe writesinxit is still pro-
nouncedsine, with a long “i”. Whenwe writecosx, we still say co-sine.And whenwe writetanx, we still
say tangent.(Sometimescasuallypeoplesay “cos”and “tan, however, it shouldn’tbe surprisingthat “sin”
is alwayspronounced“sine”!)
We can use thesedefinitionsto find the sine,cosine,and tangentvaluesfor anglesin a right triangle.
Example1:Find the sine,cosine,and tangentof angleA:
Solution:
One of the reasonsthat thesefunctionswill help us solveproblemsis that theseratioswill alwaysbe the
same,as long as the anglesare the same.Considerfor example,a trianglesimilarto triangleABC.