a) \(\sin {120^0} = \sin \left( {{{180}^0} - {{120}^0}} \right)\)\( = \sin {60^0} = \dfrac{{\sqrt 3 }}{2};\)
\(cos{120^0} = - \cos \left( {{{180}^0} - {{120}^0}} \right)\) \( = - \cos {60^0} = - \dfrac{1}{2};\)
\(\tan {120^0} = - \tan {60^0} = - \sqrt 3 ;\) \(\cot {120^0} = - \cot {60^0} = - \dfrac{1}{{\sqrt 3 }}\)
b) \(\sin {150^0} = \sin {30^0} = \dfrac{1}{2};\)\(\cos {150^0} = - \cos {30^0} = - \dfrac{{\sqrt 3 }}{2};\)
\(\tan {150^0} = - \tan {30^0} = - \dfrac{{\sqrt 3 }}{3};\) \(cot{150^0} = - \cot {30^0} = - \sqrt 3 \)
c) \(\sin {135^0} = \sin {45^0} = \dfrac{{\sqrt 2 }}{2};\)\(\cos {135^0} = - \cos {45^0} = - \dfrac{{\sqrt 2 }}{2};\)
\(\tan {135^0} = - \tan {45^0} = - 1;\) \(\cot {135^0} = - \cot {45^0} = - 1\)
