Question

9....................

Answer 1

Ответ:

tgt

Объяснение:

$\frac{sin^{4}(\frac{3\pi }{2}+t )- sin^{4}(\pi +t )}{ctgt-sin2t}= \frac{cos^{4}t- sin^{4}t}{\frac{cost}{sint} -2sintcost}={(cos^{2}t- sin^{2}t)(cos^{2}t+sin^{2}t)} *\frac{sint}{cost-2sin^{2}tcost } =(cos^{2}t- sin^{2}t)*\frac{sint}{cost(1-2sin^{2}t)} =cos2t*\frac{sint}{cost*cos2t}=\frac{sint}{cost}=tgt$