Revert trigonometric function updates.

sdk/lib/math/math.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.
 
 /**
  * Mathematical constants and functions, plus a random number generator.
- *
+ * 
  * To use this library in your code:
- *
+ * 
  *     import 'dart:math';
  */
 library dart.math;
 
 part "jenkins_smi_hash.dart";
 part "point.dart";
 part "random.dart";
 part "rectangle.dart";
 
 /**
  * Base of the natural logarithms.
  *
  * Typically written as "e".
  */
 const double E = 2.718281828459045;
 
 /**
  * Natural logarithm of 10.
- *
- * The natural logarithm of 10 is the number such that `pow(E, LN10) == 10`.
- * This value is not exact, but it is the closest representable double to the
- * exact mathematical value.
  */
 const double LN10 = 2.302585092994046;
 
 /**
  * Natural logarithm of 2.
- *
- * The natural logarithm of 2 is the number such that `pow(E, LN2) == 2`.
- * This value is not exact, but it is the closest representable double to the
- * exact mathematical value.
  */
 const double LN2 = 0.6931471805599453;
 
 /**
  * Base-2 logarithm of [E].
  */
 const double LOG2E = 1.4426950408889634;
 
 /**
  * Base-10 logarithm of [E].
@@ skipping 84 matching lines @@
     return a;
   }
   // max(-0.0, 0) must return 0.
   if (b == 0 && a.isNegative) return b;
   return a;
 }
 
 /**
  * A variant of [atan].
  *
- * Converts both arguments to [double]s.
+ * Converts both arguments to doubles.
  *
- * Returns the angle in radians between the positive x-axis
- * and the vector ([b],[a]).
- * The result is in the range -PI..PI.
+ * Returns the angle between the positive x-axis and the vector ([b],[a]).
+ * The result, in radians, is in the range -PI..PI.
  *
  * If [b] is positive, this is the same as `atan(b/a)`.
  *
  * The result is negative when [a] is negative (including when [a] is the
  * double -0.0).
  *
  * If [a] is equal to zero, the vector ([b],[a]) is considered parallel to
  * the x-axis, even if [b] is also equal to zero. The sign of [b] determines
  * the direction of the vector along the x-axis.
  *
@@ skipping 34 matching lines @@
  * - if `y` is -Infinity, the result is `1/pow(x, Infinity)`.
  *
  * This corresponds to the `pow` function defined in the IEEE Standard 754-2008.
  *
  * Notice that an [int] result cannot overflow, but a [double] result might
  * be [double.INFINITY].
  */
 external num pow(num x, num exponent);
 
 /**
- * Converts [radians] to a [double] and returns the sine of the value.
+ * Converts [x] to a double and returns the sine of the value.
  *
- * If [radians] is not a finite number, the result is NaN.
+ * If [x] is not a finite number, the result is NaN.
  */
-external double sin(num radians);
+external double sin(num x);
 
 /**
- * Converts [radians] to a [double] and returns the cosine of the value.
+ * Converts [x] to a double and returns the cosine of the value.
  *
- * If [radians] is not a finite number, the result is NaN.
+ * If [x] is not a finite number, the result is NaN.
  */
-external double cos(num radians);
+external double cos(num x);
 
 /**
- * Converts [radians] to a [double] and returns the tangent of the value.
+ * Converts [x] to a double and returns the tangent of the value.
  *
- * The tangent function is equivalent to `sin(radians)/cos(radians)` and may be
- * infinite (positive or negative) when `cos(radians)` is equal to zero.
- * If [radians] is not a finite number, the result is NaN.
+ * The tangent function is equivalent to `sin(x)/cos(x)` and may be
+ * infinite (positive or negative) when `cos(x)` is equal to zero.
+ * If [x] is not a finite number, the result is NaN.
  */
-external double tan(num radians);
+external double tan(num x);
 
 /**
- * Converts [x] to a [double] and returns its arc cosine in radians.
+ * Converts [x] to a double and returns the arc cosine of the value.
  *
  * Returns a value in the range 0..PI, or NaN if [x] is outside
  * the range -1..1.
  */
 external double acos(num x);
 
 /**
- * Converts [x] to a [double] and returns its arc sine in radians.
+ * Converts [x] to a double and returns the arc sine of the value.
  *
  * Returns a value in the range -PI/2..PI/2, or NaN if [x] is outside
  * the range -1..1.
  */
 external double asin(num x);
 
 /**
- * Converts [x] to a [double] and returns its arc tangent in radians.
+ * Converts [x] to a double and returns the arc tangent of the value.
  *
  * Returns a value in the range -PI/2..PI/2, or NaN if [x] is NaN.
  */
 external double atan(num x);
 
 /**
- * Converts [x] to a [double] and returns the positive square root of the value.
+ * Converts [x] to a double and returns the positive square root of the value.
  *
  * Returns -0.0 if [x] is -0.0, and NaN if [x] is otherwise negative or NaN.
  */
 external double sqrt(num x);
 
 /**
- * Converts [x] to a [double] and returns the natural exponent, [E],
+ * Converts [x] to a double and returns the natural exponent, [E],
  * to the power [x].
  *
  * Returns NaN if [x] is NaN.
  */
 external double exp(num x);
 
 /**
- * Converts [x] to a [double] and returns the natural logarithm of the value.
+ * Converts [x] to a double and returns the natural logarithm of the value.
  *
  * Returns negative infinity if [x] is equal to zero.
  * Returns NaN if [x] is NaN or less than zero.
  */
 external double log(num x);