Answer:
The value of cos Ф is ± [tex]\frac{1}{2}[/tex]
Step-by-step explanation:
There are important rules for sin Ф and cos Ф
∵ sin Ф = [tex]\frac{\sqrt{3}}{2}[/tex]
∴ sin²Ф = [tex](\frac{\sqrt{3}}{2})^{2}[/tex]
∴ sin²Ф = [tex]\frac{3}{4}[/tex]
→ By using the third rule above
∵ cos²Ф = 1 - sin²Ф
∴ cos²Ф = 1 - [tex]\frac{3}{4}[/tex]
∴ cos²Ф = [tex]\frac{1}{4}[/tex]
→ Take square root for both sides
∴ cos Ф = ± [tex]\frac{1}{2}[/tex]
∴ The value of cos Ф is ± [tex]\frac{1}{2}[/tex]
