Question

The value $co{t}^2{30}^{\circ }-2co{s}^2{60}^{\circ }-\frac{3}{4}se{c}^2{45}^{\circ }-4si{n}^2{30}^{\circ }$ is

• A. 0
• B. 1
• C. -1
• D. 2

Answer 1

The correct option is A

0

$co{t}^2{30}^{\circ }-2co{s}^2{60}^{\circ }-\frac{3}{4}se{c}^2{45}^{\circ }-4si{n}^2{30}^{\circ }$

$=(\sqrt{3}{)}^2-2(\frac{1}{2}{)}^2-\frac{3}{4}(\sqrt{2}{)}^2-4(\frac{1}{2}{)}^2$

$=3-\frac{1}{2}-\frac{3}{2}-1$

$=0$