### Contour plot restricted to a region defined by multiple inequalities

I'm trying to use `contour_plot`

for plotting contours defined only in a region of the parameter space, namely only in the triangle defined by the vertices $(0,0), (1/2,\sqrt{3}/2), (1,0)$. The faces of this triangle are defined by the intersections of the x-axis and the lines of equation $y=\sqrt{3}x$ and $y=-\sqrt{3}x+\sqrt{3}$.

Contour_plot has the nice option `region`

, but it seems that `region`

only accepts one condition, i.e. only one boundary because the documentation specifies that `region`

must be of the form $f(x,y)$ and this is interpreted by the code of `countour_plot`

as $f(x,y)>0$, i.e. `countour_plot`

plots all points such that $f(x,y)>0$. Is there a way to do what I need with this version of `contour_plot`

?

The following represents what I’d like to do but it does not work. It does not throw an error but only takes into account the first condition

`contour_plot((x^2) * cos(x*y), (x,-10,5), (y,-5,5), region=(-sqrt(3)*x-y and -sqrt(3)*x+sqrt(3)-y), fill=True, contours=30)`

Note that there are other imperfect solutions to this problem like using a white polygon to hide the part of the plot I do not want to see. However, this "solution" is not desirable because the maximum and minimum values of `contour_plot`

will not be defined with respect to the region I am trying to show (I hope this is clear; I can show an example if this is not).