Update documentation on trignometric functions.

pkg/dev_compiler/tool/input_sdk/patch/math_patch.dart

 // Copyright (c) 2012, 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.
 
 // Patch file for dart:math library.
 import 'dart:_foreign_helper' show JS;
 import 'dart:_js_helper' show patch, checkNum;
 import 'dart:typed_data' show ByteData;
 
 @patch
 num/*=T*/ min/*<T extends num>*/(num/*=T*/ a, num/*=T*/ b) =>
     JS('num', r'Math.min(#, #)', checkNum(a), checkNum(b)) as num/*=T*/;
 
 @patch
 num/*=T*/ max/*<T extends num>*/(num/*=T*/ a, num/*=T*/ b) =>
     JS('num', r'Math.max(#, #)', checkNum(a), checkNum(b)) as num/*=T*/;
 
 @patch
 double sqrt(num x) => JS('num', r'Math.sqrt(#)', checkNum(x));
 
 @patch
-double sin(num x) => JS('num', r'Math.sin(#)', checkNum(x));
+double sin(num radians) => JS('num', r'Math.sin(#)', checkNum(radians));
 
 @patch
-double cos(num x) => JS('num', r'Math.cos(#)', checkNum(x));
+double cos(num radians) => JS('num', r'Math.cos(#)', checkNum(radians));
 
 @patch
-double tan(num x) => JS('num', r'Math.tan(#)', checkNum(x));
+double tan(num radians) => JS('num', r'Math.tan(#)', checkNum(radians));
 
 @patch
 double acos(num x) => JS('num', r'Math.acos(#)', checkNum(x));
 
 @patch
 double asin(num x) => JS('num', r'Math.asin(#)', checkNum(x));
 
 @patch
 double atan(num x) => JS('num', r'Math.atan(#)', checkNum(x));
 
@@ skipping 279 matching lines @@
       // last range of k*max .. 256**byteCount.
       // TODO: Consider picking a higher byte count if the last range is a
       // significant portion of the entire range - a 50% chance of having
       // to use two more bytes is no worse than always using one more.
       if (random - result + max < randomLimit) {
         return result;
       }
     }
   }
 }