Answer:
Step-by-step explanation:
[tex]\sin \left(30^{\circ \:}\right)+\cos \left(60^{\circ \:}\right)-1\\\\\mathrm{Use\:the\:following\:trivial\:identity}:\\\quad \sin \left(30^{\circ \:}\right)=\frac{1}{2}\\\\\mathrm{Use\:the\:following\:trivial\:\\identity}:\\\quad \cos \left(60^{\circ \:}\right)=\frac{1}{2}\\\\=\frac{1}{2}+\frac{1}{2}-1\\\\=0[/tex]
[tex]\\\cos \left(60^{\circ \:}\right)+\tan \left(30^{\circ \:}\right)-1\\\\\mathrm{Use\:the\:following\:trivial\:identity}:\\\quad \cos \left(60^{\circ \:}\right)=\frac{1}{2}\\\mathrm{Use\:the\:following\:trivial\:identity}:\\\quad \tan \left(30^{\circ \:}\right)=\frac{\sqrt{3}}{3}\\\\=\frac{1}{2}+\frac{\sqrt{3}}{3}-1\\\\=-\frac{1}{2}+\frac{\sqrt{3}}{3}[/tex]
