Question

$tgfrac{3pi}{4} +cosfrac{5pi}{3} *sinfrac{7pi}{6} -(sinfrac{2pi}{3} )^2$
Помогите пожалуйста срочно нужно решить

Answer 1

$tg frac{3pi}{4} + cos frac{5pi}{3} times sin frac{7pi}{6} - {( sin frac{2pi}{3} ) }^{2} = \ = tg frac{4pi - pi}{4} + cos frac{6pi - pi}{3} times sin frac{6pi + pi }{6} - \ - {( sin frac{3pi - pi}{3} ) }^{2} = tg( frac{4pi}{4} - frac{pi}{4}) + \ + cos( frac{6pi}{3} - frac{pi}{3}) times sin( frac{6pi}{6} + frac{pi}{6}) - {( sin (frac{3pi}{3} - frac{pi}{3}) ) }^{2} = \ = tg(pi - frac{pi}{4} ) + cos (2pi - frac{pi}{3} )times sin (pi + frac{pi}{6}) - \ - {( sin(pi - frac{pi}{3} )) }^{2} = - tg frac{pi}{4} + cos frac{pi}{3} times ( - sin frac{pi}{6}) - {( sin frac{pi}{3} ) }^{2} = \ = - tg frac{pi}{4} - cos frac{pi}{3} times sin ( frac{pi}{2} - frac{pi}{3} )- {( sin frac{pi}{3} ) }^{2} = \ = - 1 - cos frac{pi}{3} times cos frac{pi}{3} - {( sin frac{pi}{3} ) }^{2} = - 1 - (cos frac{pi}{3} )^2 - \ - (sin frac{pi}{3} )^2 = - 1 - (cos^2 frac{pi}{3} + sin^2 frac{pi}{3} )=-1-1=-2$

Answer 2

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