Show inline operator in README example

README.md

@@ -77,7 +77,7 @@ y = 2*np.cos(X[:, 3]) + X[:, 0]**2 - 2
 # Learn equations
 equations = pysr(X, y, niterations=5,
         binary_operators=["plus", "mult"],
-        unary_operators=["cos", "exp", "sin"])
+        unary_operators=["cos", "exp", "sin", "inv(x) = 1/x"])
 
 ...# (you can use ctl-c to exit early)