Question

If cos x= √2/2 and x is a fourth quadrant angle, evaluate tan 2x

Answer 1

Since x is a fourth quadrant angle, it is between 270° and 360° (or between -90° and 0°).

So, calculating x, we have:

`\begin{gathered} \cos (x)=\frac{\sqrt[]{2}}{2} \\ x=\cos ^(-1)(\frac{\sqrt[]{2}}{2}) \\ x=-45\degree \end{gathered}`

Now, multiplying x by 2, we have -45 * 2 = -90°.

So the tangent of 2x is:

Therefore tan 2x is undefined.