Fix typo.

corelib/src/math.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Dart core library.
 
 class Math {
   /**
    * Base of the natural logarithms.
    */
@@ skipping 66 matching lines @@
           // [min] must also distinguish between -0.0 and 0.0.
           if (a is double) {
             if (a == 0.0) {
               // a is either 0.0 or -0.0. b is either 0.0, -0.0 or NaN.
               // The following returns -0.0 if either a or b is -0.0, and it
               // returns NaN if b is NaN.
               return (a + b) * a * b;
             }
           }
           // Check for NaN and b == -0.0.
-          if (a == 0 && b.isNegative() || b.isNan()) return b;
+          if (a == 0 && b.isNegative() || b.isNaN()) return b;
           return a;
         }
         return a;
       }
       throw new IllegalArgumentException(b);
     }
     throw new IllegalArgumentException(a);
   }
 
   /**
@@ skipping 53 matching lines @@
   static double sin(num x) => MathNatives.sin(x);
   static double cos(num x) => MathNatives.cos(x);
   static double tan(num x) => MathNatives.tan(x);
   static double acos(num x) => MathNatives.acos(x);
   static double asin(num x) => MathNatives.asin(x);
   static double atan(num x) => MathNatives.atan(x);
   static double sqrt(num x) => MathNatives.sqrt(x);
   static double exp(num x) => MathNatives.exp(x);
   static double log(num x) => MathNatives.log(x);
 }