Ohfive
is
bak from math tution learn the stupid "Toa Cah Soh"
Yiling
says
What is that?
Ohfive
says
tangent(tan),cosine(cos) and sine(sin)
Yiling
says
Oh i see. Haha.
Ohfive
says
yup haha kinda of stupid 
Ohfive
says
O.o cant rmb the formula haha