# Math Help - Simplify the Expression (Double-Angle or Half-Angle)

1. ## Simplify the Expression (Double-Angle or Half-Angle)

Hello,

Can someone please help me with simplifying this problem?

1) 2tan7 / 1-tan7
2) sqrt(1-cos30 /2)

2. Originally Posted by l flipboi l
Hello,

Can someone please help me with simplifying this problem?

1) 2tan7 / 1-tan7

2) sqrt(1-cos30 /2)
(1) double angle should be $\frac{2\tan(7)}{1 - \tan^2(7)} = \tan(14)
$

(2) $\sqrt{\frac{1-\cos(30)}{2}} = \sin(15)$