Question

If ${\tan }^2{45}^0-{\cos }^2{30}^0=x\sin {45}^0\cos {45}^0,thenx=?$

• A. 2
• B. 1/2
• C. -1/2
• D. 1
• E. √3 /2

Answer 1

The correct option is B

1/2

$\begin{array}{c}{1}^2-{\left(\frac{\sqrt{3}}{2}\right)}^2=x\times \frac{1}{\sqrt{2}}\times \frac{1}{\sqrt{2}}\\ \Rightarrow 1-\frac{3}{4}=\frac{x}{2}\Rightarrow x=\frac{1}{2}\end{array}$