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Probably newbie question
Is it possible to input logarithms with a fractional base? When I try it creates a rational expression. Parentheses don't work either. Or, must I change the base?
Thanks
Joe
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Joseph Stavitsky wrote:
Probably newbie question
Is it possible to input logarithms with a fractional base?
Yes, as long as the base is positive and does not not equal one.
When I try it creates a rational expression.
What do you mean by that and why do you think thats not as it should be?
Parentheses don't work either. Or, must I change the base?
You don't show what you do and don't say what you expect, so we can't tell. Obviously when you want the logarithm of a base unequal to 10 you have to state that.
You know that in Mathcad log(a) means the logarithm of a to base 10, while log(a,b) ist the logarithm to base b of a.
If you want to take the logarithm of base 2/3 from an argument like 27/8 (which is obviously -3), you would type log(27/8, 2/3)=
Hi Joseph,
One example of a logarithm with a fractional base is the natural logarithm ln(x), with base 2.71828182845....
A logarithm of a value x (> 0) to any base b (> 0) can be computed as ln(x)/ln(b).
Or do you mean something else...?
Luc
LucMeekes wrote:
Hi Joseph,
One example of a logarithm with a fractional base is the natural logarithm ln(x), with base 2.71828182845....
A logarithm of a value x (> 0) to any base b (> 0) can be computed as ln(x)/ln(b).
Any base but b=1!
Joseph Stavitsky wrote:
Probably newbie question
Is it possible to input logarithms with a fractional base?
Yes, as long as the base is positive and does not not equal one.
When I try it creates a rational expression.
What do you mean by that and why do you think thats not as it should be?
Parentheses don't work either. Or, must I change the base?
You don't show what you do and don't say what you expect, so we can't tell. Obviously when you want the logarithm of a base unequal to 10 you have to state that.
You know that in Mathcad log(a) means the logarithm of a to base 10, while log(a,b) ist the logarithm to base b of a.
If you want to take the logarithm of base 2/3 from an argument like 27/8 (which is obviously -3), you would type log(27/8, 2/3)=
That last part is what I was missing, thanks. I was trying to input it as it is traditionally typeset.