diff --git a/arraycontext/fake_numpy.py b/arraycontext/fake_numpy.py
index 43ec6b696e4c8aebf715d11e12e91c0bd037d216..2de78d1b6905cc155e665300c7eefd58e3a03247 100644
--- a/arraycontext/fake_numpy.py
+++ b/arraycontext/fake_numpy.py
@@ -155,7 +155,7 @@ class BaseFakeNumpyNamespace:
             delta_actx = self._array_context.from_numpy(delta)
             # sequences with 0 items or 1 item with endpoint=True (i.e. div <= 0)
             # have an undefined step
-            step = np.NaN
+            step = np.nan
             # Multiply with delta to allow possible override of output class.
             y = y * delta_actx
 
diff --git a/arraycontext/impl/jax/fake_numpy.py b/arraycontext/impl/jax/fake_numpy.py
index 27799cfebcd0e836ebc00f659aa80762b0203cde..d20448a4d4060c8667485ada97b582ff961ed42b 100644
--- a/arraycontext/impl/jax/fake_numpy.py
+++ b/arraycontext/impl/jax/fake_numpy.py
@@ -130,8 +130,8 @@ class EagerJAXFakeNumpyNamespace(BaseFakeNumpyNamespace):
         from arraycontext import rec_multimap_reduce_array_container
 
         def _rec_vdot(ary1, ary2):
-            common_dtype = np.find_common_type((ary1.dtype, ary2.dtype), ())
-            if dtype not in [None, common_dtype]:
+            common_dtype = np.result_type(ary1, ary2)
+            if dtype not in (None, common_dtype):
                 raise NotImplementedError(
                     f"{type(self).__name__} cannot take dtype in vdot.")