Hello, white_cap!
If .
find the value of: .
Square both equations:
. .
. .
Add the equations: .
Therefore: .
Hello again, white_cap!
It's one of those thing we learn to watch for.
When I see both and , that technique come to mind
It turns up regularly in Parametric Equations.
Example: .
Eliminate the parameter .
Get an equation involving and (only).
We have: .
Square the equations: .
Add the equations: .
Therefore: . . . . . There!