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+The tolerance (DOUBLE_EQUALITY_TOLERANCE) is too small for the unit test testRaiseARealNumberToAPositiveRationalNumber(). 
+The calculation of exp() is too numerically sensitive to whether the user implements 
+```
+Math.pow(Math.pow(x, numerator), 1.0/denominator)
+```
+or
+```
+Math.pow(Math.pow(x, 1.0/denominator), numerator)
+```
+Both are mathematically equivalent, however, the first one fails the unit test whereas the second passes. 
+Furthermore, the instructions to the exercise bias the user towards the first implementation.