Find the domain of the function yLn4xy1SolutionWe must have

Find the domain of the function? y=Ln(4x-y+1)

Solution

We must have 4x-y+1>0 (this is because the logarithmic function is undefined for negative values)
Thus, we must have
y<4x+1
So, the Domain D:={(x,y) in R²|y<4x+1}