p = sin 40 q = cos110 find expression for cos140 and find expression for tan140

sin(40)=sin(180-40) or sin(40) = sin(140) = p

cos(140) = -√(1-sin(140)^{2}) = -√(1-p^{2}) Cosine is negative in the 2nd quadrant.

tan(140) = sin(140)/cos(140) = -p/√(1-p^{2}) Tangent is also negative in the 2nd quadrant

.