Use the Half-Angle Formulas to Determine the Exact Value of the Given

Multiple Choice

Use the half-angle formulas to determine the exact value of the given trigonometric expression. ​​ $$\tan \frac { 3 \pi } { 8 }$$ ​

A) ​ $\tan \frac { 3 \pi } { 8 } = \sqrt { 2 } - 1$
B) ​ $\tan \frac { 3 \pi } { 8 } = \frac { \sqrt { 2 - \sqrt { 2 } } } { 4 }$
C) ​ $\tan \frac { 3 \pi } { 8 } = \sqrt { 2 + \sqrt { 2 } }$
D) ​ $\tan \frac { 3 \pi } { 8 } = \sqrt { 2 } + 1$ ​
E) ​ $\tan \frac { 3 \pi } { 8 } = - \frac { \sqrt { 2 + \sqrt { 2 } } } { 4 }$