where a is any real number. We understand intuitively what it means to raise x to the power of a natural
number n: we just multiply n copies of x together. We know what it means to raise x to the ¡n power:
just divide 1 by xn. Now we are asked to raise x to the power of a, where a is any real number, but what
does, say, 3¼ mean? It does not make sense to multiply ¼ copies of 3 together. We have been ignoring this
question since we defined exponential functions, but now we intend to give you an answer.
First, restrict x to the positive real numbers and consider the exponential function ex and the natural
logarithmic function ln x. There is a great relationship built into ex and ln x: if we compose these two
functions with each other in either order, the resulting function is x: