randRange(3, 8)
randRange(2, 4)
randFromArray([
function(x, y) { return ["+", ["*", C, x], y]; },
function(x, y) { return ["-", ["*", C, x], y]; },
function(x, y) { return ["+", x, ["*", C, y]]; },
function(x, y) { return ["-", x, ["*", C, y]]; },
function(x, y) { return ["-", ["*", C, x], ["*", D, y]]; },
function(x, y) { return ["-", ["*", D, x], ["*", C, y]]; },
function(x, y) { return ["*", x, ["-", y, C]]; },
function(x, y) { return ["*", ["-", C, x], y]; },
function(x, y) { return ["+", ["^", x, 2], ["*", D, ["^", y, 2]]]; },
function(x, y) { return ["+", ["*", D, ["^", x, 2]], ["^", y, 2]]; },
function(x, y) { return ["-", ["^", x, 2], ["*", D, ["^", y, 2]]]; },
function(x, y) { return ["-", ["*", D, ["^", x, 2]], ["^", y, 2]]; },
function(x, y) { return ["-", ["*", D, x], C]; },
function(x, y) { return ["+", ["*", C, y], D]; },
function(x, y) { return ["+", ["*", x, y], ["*", D, x], ["-", y]]; }
])
randRange(-6, 6)
randRange(-6, 6)
expr(FUN("x", "y"))
expr(FUN(X, Y))
expr(FUN(X, Y), true)
!isNaN(expr(FUN(0, NaN), true))
!isNaN(expr(FUN(NaN, 0), true))
If x binop(1) y = TEXT, find X binop(1) Y.
VALU
Substitute in
x = X
y = Y
x = X and y = Y
to get SUBS.
Simplify the expression to get VALU.