a) \(\begin{array}{l}2\sin 30^\circ - 2c{\rm{os}}60^\circ + tg45^\circ \\ = 2\sin 30^\circ - 2\sin 30^\circ + tg45^\circ \\ = tg45^\circ \\ = 1.\end{array}\)
b) \(\begin{array}{l}\sin 45^\circ + \cot g60^\circ .c{\rm{os30}}^\circ \\ = \sin 45^\circ + tg30^\circ .c{\rm{os30}}^\circ \\{\rm{ = sin}}45^\circ + \dfrac{{\sin 30^\circ }}{{{\rm{cos30}}^\circ }}.c{\rm{os30}}^\circ \\ = \sin 45^\circ + \sin 30^\circ \\ = \dfrac{{\sqrt 2 }}{2} + \dfrac{1}{2}\\ = \dfrac{{\sqrt 2 + 1}}{2}.\end{array}\)
c) \(\begin{array}{l}\cot g44^\circ .\cot g45^\circ .\cot g46^\circ \\ = tg46^\circ .\cot g46^\circ .\cot g45^\circ \\ = \cot g45^\circ \\ = 1.\end{array}\)
