s i n 3 π 4 = 2 2 ; c o s 3 π 4 = − 2 2 ; t a n 3 π 4 = − 1 ; c s c 3 π 4 = 2 ; s e c 3 π 4 = − 2 ; c o t 3 π 4 = − 1 {\displaystyle sin{\frac {3\pi }{4}}={\frac {\sqrt {2}}{2}};cos{\frac {3\pi }{4}}=-{\frac {\sqrt {2}}{2}};tan{\frac {3\pi }{4}}=-1;csc{\frac {3\pi }{4}}={\sqrt {2}};sec{\frac {3\pi }{4}}={-{\sqrt {2}}};cot{\frac {3\pi }{4}}=-1}