# RegionPlot - not a valid region to plot

I have two regions like this

reg1 = ImplicitRegion[(-5. + x)^2 + (-3. + y)^2 <= 0.25 || (0.386909 + x Tan[25 \[Degree]]
<= y <= 5.61309 - x Tan[25 \[Degree]] && 0 <= x <= 5.), {x, y}];

reg2 = ImplicitRegion[(-5. + x)^2 + (-3. + y)^2 <= 0.49 || (0.166233 + x Tan[25 \[Degree]]
<= y <= 5.83377 - x Tan[25 \[Degree]] && 0 <= x <= 5.), {x, y}];

Show[RegionPlot[reg1, AspectRatio -> Automatic], RegionPlot[reg2, AspectRatio -> Automatic]] I need to see and work with their difference

RegionPlot[RegionDifference[reg2,reg1], AspectRatio -> Automatic]


but it brings about an error

RegionPlot::invplotreg: {RegionDifference[ImplicitRegion[Plus[<<2>>]^2+Plus[<<2>>]^2<=0.49||(0.166233 +Times[<<2>>]<=y<=5.83377 +Times[<<3>>]&&0<=x<=5.),{x,y}],ImplicitRegion[Plus[<<2>>]^2+Plus[<<2>>]^2<=0.25||(0.386909 +Times[<<2>>]<=y<=5.61309 +Times[<<3>>]&&0<=x<=5.),{x,y}]]} is not a valid region to plot. >>

• What are w3 and w2? Maybe you meant reg2 and reg1; in that case RegionPlot[RegionDifference[reg2, reg1], AspectRatio -> Automatic] works with no problems. – corey979 Sep 23 '16 at 12:10
• Yes, sorry, I meant reg2, reg1. But it still doesn't work for me. – T. Rihacek Sep 23 '16 at 12:51
• Try quitting the kernel, maybe you have some old definitions. – corey979 Sep 23 '16 at 12:57
• works here too, maybe a version issue. – george2079 Sep 23 '16 at 18:22
• Works in version 11 on Windows 10 – Simon Woods Sep 23 '16 at 18:57

RegionDifference @@ (DiscretizeRegion /@ {reg2, reg1}) 