Answer:
cos B = sin A
Step-by-step explanation:
Given: Δ ABC is a right angles triangle
m∠A + m∠B = 90°
To find: Cos B equals to
Figure is attached.
Using trigonometric ratios in Δ ABC,
We get,
\(cos\,B\,=\,\frac{base}{hypotenuse}\,=\,\frac{CB}{AB}\)
\(sin\,B\,=\,\frac{altitude}{hypotenuse}\,=\,\frac{AC}{AB}\)
\(cos\,A\,=\,\frac{altitude}{hypotenuse}\,=\,\frac{AC}{AB}\)
\(sin\,B\,=\,\frac{base}{hypotenuse}\,=\,\frac{CB}{AB}\)
So, From above it is clear
cos B = sin A
Therefore, cos B = sin A
