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 \(\theta\)
Then the trigonometric ratios are the following:
\(sin\,\theta=\frac{AC}{AB}\)
\(cos\,\theta=\frac{CB}{AB}\)
\(tan\,\theta=\frac{AC}{CB}\)
\(cosec\,\theta=\frac{AB}{AC}\)
\(sec\,\theta=\frac{AB}{CB}\)
\(tan\,\theta=\frac{CB}{AC}\)
So, clearly \(cos\,\theta=\frac{Adjacent}{Hypotenuse}\)
Its \(sin\,\theta=\frac{Opposite}{Hypotenuse}\)
