Hi there,
So we know that some number [math]b^n[/math] is [math]b[/math] multiplied by itself [math]n[/math] times.
What about roots? The logic would imply that we take [math]b^\frac{1}{n}[/math] as being [math]b[/math] multiplied by itself [math]\frac{1}{n}[/math] times. I'm a little vague on the underlying mechanisms of taking roots and fractional exponents. I am aware that fractional exponents and roots are computed using logarithms but how?
As an example:
[math]10^\frac{5}{2} = 10^{2 + \frac{1}{2}} = 10^2 10^\frac{1}{2} \approx 100(3.162) \approx 316.2[/math]
I can see that breaking the exponent apart gives a sum of a whole power [math]2[/math] and a square root. The whole power is straightforward as a result of taking [math]10[/math] as a factor twice but what about the square root? I'd like to know in more detail how this is calculated without using a calculator and without resorting entirely to a root finding algorithm such as Newton's method. What is the underlying mechanism?
Thanks!
EDIT:
On a side note, as a result of playing around with the idea of raising [math]2[/math] to the following powers in the sequence [math]0,\frac{1}{10},\frac{1}{5},\frac{3}{10},\frac{2}{5},\frac{1}{2},\frac{3}{5},\frac{7}{10},\frac{4}{5},\frac{9}{10},1[/math] I get various values and taking the ratio of the current value and the previous value (starting from the second expression) gives me a constant of [math]\approx 1.072[/math]. ie.
[math]A: 2^0 = 1[/math]
[math]B: 2^{\frac{1}{10}} \approx 1.072 1[/math]
[math]\frac{B}{A} \approx 1.072[/math]
[math]C: 2^{\frac{1}{5}} \approx 1.149 1[/math]
[math]\frac{C}{B} \approx 1.072[/math]
[math]D: 2^{\frac{3}{10}} \approx 1.231 1[/math]
[math]\frac{D}{C} \approx 1.072[/math]
[math]...[/math]
I can see that there must be some kind of relationship here, but not seeing it...