Answer:
False, The cosine of an angle is the ratio of the opposite side over the hypotenuse.
Let ΔABC is a right angled triangle, ∠C = 90°
Figure is attached.
let ∠B be [tex]\theta[/tex]
Then the trigonometric ratios are the following:
[tex]sin\,\theta=\frac{AC}{AB}[/tex]
[tex]cos\,\theta=\frac{CB}{AB}[/tex]
[tex]tan\,\theta=\frac{AC}{CB}[/tex]
[tex]cosec\,\theta=\frac{AB}{AC}[/tex]
[tex]sec\,\theta=\frac{AB}{CB}[/tex]
[tex]tan\,\theta=\frac{CB}{AC}[/tex]
So, clearly [tex]cos\,\theta=\frac{Adjacent}{Hypotenuse}[/tex]
Its [tex]sin\,\theta=\frac{Opposite}{Hypotenuse}[/tex]
