The Story of the Youth Who Went Forth to Learn What Fear Was undressed yourself to teach us fear.." as in figuratively "put something on, you've put yourself out to teach fear."). The Story of the Youth Who Went Forth to Learn What Fear Was "The Story of the Youth Who Went Forth to Learn What Fear Was" or "The Story of a Boy Who Went Forth to Learn Fear" () is a German folktale collected by the Brothers Grimm. It is tale number 4 in the collection. It was also included by Andrew Lang in "The Blue Fairy Book" (1889). The Grimms' first, 1812 edition contained a much shorter version, "Good Bowling
Irrational number if complex number exponentiation is used). An example that provides a simple constructive proof is The base of the left side is irrational and the right side is rational, so one must prove that the exponent on the left side, formula_17, is irrational. This is so because, by the formula relating logarithms with different bases, which we can assume, for the sake of establishing a contradiction, equals a ratio "m/n" of positive integers. Then formula_19 hence formula_20 hence formula_21 hence formula_22, which is a contradictory pair of prime factorizations and hence violates the fundamental theorem of arithmetic (unique prime factorization).