Đáp án:
$\begin{array}{l}
a)2\sin {30^0} - 2\cos {60^0} + \tan {45^0}\\
= 2.\dfrac{1}{2} - 2.\dfrac{1}{2} + \dfrac{{\sqrt 2 }}{2}\\
= \dfrac{{\sqrt 2 }}{2}\\
b)\sin {45^0} + \cot {60^0}.\cos {30^0}\\
= \dfrac{{\sqrt 2 }}{2} + \sqrt 3 .\dfrac{{\sqrt 3 }}{2}\\
= \dfrac{{\sqrt 2 }}{2} + \dfrac{3}{2}\\
= \dfrac{{3 + \sqrt 2 }}{2}\\
c)\cot {44^0}.\cot {45^0}.\cot {46^0}\\
= \tan \left( {{{90}^0} - {{44}^0}} \right).\cot {46^0}.\cot {45^0}\\
= \tan {46^0}.\cot {46^0}.1\\
= 1
\end{array}$
