Question

evaluate the following;
a)cos 1050 degree
b)cosec (-585 degree)
c)cot 495 degree
d)tan 120 degree

Answer 1

$$\begin{gathered} \left(\mathrm{a}\right)\cos \left(1050°\right)=\cos \left(1080-30\right) \\ =\cos \left(30\right)=\frac{\sqrt{3}}{2} \\ \left(\mathrm{b}\right)\mathrm{cosec}\left(-585\right)=-\mathrm{cosec}\left(585\right) \\ =-\mathrm{cosec}\left(360+225\right) \\ =-\mathrm{cosec}\left(225\right) \\ =-\mathrm{cosec}\left(180+45\right) \\ =\mathrm{cosec}45=\sqrt{2} \\ \left(\mathrm{c}\right)\cot \left(495\right)=\cot \left(360+135\right) \\ =\cot \left(135\right)=\cot \left(90+45\right) \\ =-\tan 45=-1\mathrm{ANS}... \\ \left(\mathrm{d}\right)\tan \left(120\right)=\tan \left(90+30\right) \\ =-\cot 30=-\sqrt{3}\mathrm{ANS}... \end{gathered}$$