Hi there!
[tex]\large\boxed{cos(\frac{\theta}{2} )= \frac{3}{\sqrt{7}}}[/tex]
[tex]\large\boxed{tan(\frac{\theta}{2}) = \frac{\sqrt{5}}{3}}[/tex]
Begin by recalling that:
sin(θ) = O/H, so:
Opposite side = 3√5
Hypotenuse = 7
We can solve for the adjacent sign using the Pythagorean Theorem:
7² = (3√5)² + b²
49 = 45 + b²
b² = 4
b = 2.
Thus, cosθ = 2/ 7
Use the half angle identity to solve for cos(θ/2):
cos(θ/2) = √(1 + cosθ)
Plug in the value of cosθ:
= √(1 + 2/7) = √9/7, or 3 /√7
Thus:
[tex]cos(\frac{\theta}{2}) = \frac{3}{\sqrt{7}}[/tex]
Calculate tan(θ/2) using the same process but with a different formula:
tan(θ/2) = √(1 - cosθ / 1 + cosθ)
Substitute in the value of cosθ:
tan(θ/2) = √(1 - 2/7)/(1 + 2/7)
= √(5/7)/(9/7) = √5/9 = √5/3
