Question

Find the value of
1.Sin(-25π/4)
Cot 570°
Tan480°

Answer 1

Answer:

$\sin( - \frac{25\pi}{4} ) = - \sin( \frac{25\pi}{4} ) = - \sin(6\pi + \frac{\pi}{4} ) = - \sin( \frac{\pi}{4} ) = - \frac{1}{ \sqrt{2} }$

$\cot(570) = \cot(540 + 30) = \cot(30) = \sqrt{3}$

$\tan(480) = \tan(360 + 120) = \tan(120) = \tan(90 + 30) = - \cot(30) = - \sqrt{3}$