Question

tan (1/2 cos ^-1 sqrt5/3)=? sqrt is only for 5?

Answer 1

calculator?

Answer 2

No...

Answer 3

Let \(\cos^-1\large\frac{\sqrt5}{3}\) be \(\alpha\).
Then \(\cos\alpha=\large\frac{\sqrt5}{3}\)

\(\tan\alpha=\large\frac{2}{\sqrt5}\)
\(\tan\alpha=\large\frac{2\tan\frac{\alpha}{2}}{1-tan^2\frac{\alpha}{2}}\)

Solve for tan(\(\alpha\)/2)
that's vat u need to find.