Answer:
cosΘ = [tex]\frac{4}{5}[/tex]
Step-by-step explanation:
Using the trigonometric identity
sin²x + cos²x = 1 ⇒ cosx = ± [tex]\sqrt{1-sin^2x}[/tex]
Given
sinΘ = [tex]\frac{3}{5}[/tex], then
cosΘ = ± [tex]\sqrt{1-(3/5)^2}[/tex] = ± [tex]\sqrt{1-\frac{9}{25} }[/tex] = ± [tex]\sqrt{\frac{16}{25} }[/tex] = ± [tex]\frac{4}{5}[/tex]
Since Θ is in first quadrant then cosΘ > 0
cosΘ = [tex]\frac{4}{5}[/tex]
