This can be expanded through the tangent angle addition formula:
tan(α+β)=tanα+tanβ1−tan -α + tanβ
Thus,tan(x+y)=tanx+tany1−tan x tany
Hope it helps you
Answer; there is literally no solution. it has to be a negative number.

Step-by-step explanation:

Answer:
what do you need help on?
To solve for the longest side, the hypotenuse, you have to use the pythagorean theorem. It will be 10^2 + 9^2 = c^2. 100 + 81 =c^2.
c^2 = 181 so c = sqrt(181).
to find sin of A do opposite/hypotenuse which gives you 9/sqrt(181)
to find cos of A do adjacent/hypotenuse which gives you 10/sqrt(181)