Question

Consider this right triangle

Answer 1

Answer:
cos D
sin E

Explanation:
In right-angled triangles, the following trig function can be applied:
sin θ = opposite / hypotenuse
cos θ = adjacent / hypotenuse
tan θ = opposite / adjacent

Now, for the given triangle:
We want the functions including x and y.
Let's check the relation between these variables and each angle in the triangle:
1- For angle D:
x is the adjacent side
y is the hypotenuse
Based on the above rules:
cos D = adjacent / hypotenuse
cos D = x / y

2- For angle E:
x is the opposite side
y is the hypotenuse
Based on the above rules:
sin E = opposite / hypotenuse
sin E = x / y

Hope this helps :)