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needed: exponential function with any a real (float) base
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Guru

Joined: Sat Mar 01, 2008 12:52 pm
Posts: 1030
needed: exponential function with any a real (float) base
hi to all,
I need an exponential function with any a real (floating point) base, similar to exp(x) with Euler's number (e) as a base,
but with any a real base and with any a real exponent, e.g.

1,5^x
2^x
e^x (=exp(x))
3^x
10^x
PI^e

I know, there should be a math formula to converse exp(x) to any other real (float) base, but school maths are long gone...

_________________
regards,
HaWe aka Ford
#define S sqrt(t+2*i*i)<2
#define F(a,b) for(a=0;a<b;++a)

Tue Jul 29, 2008 6:00 pm
Rookie

Joined: Wed Jul 23, 2008 12:48 am
Posts: 19
Location: Germany

a^x = exp( x * log(a) )
with log being the natural logarithm

Last edited by zeron on Wed Jul 30, 2008 6:01 am, edited 1 time in total.

Wed Jul 30, 2008 3:43 am
Guru

Joined: Sat Mar 01, 2008 12:52 pm
Posts: 1030

uuuh...yeah.
looks familiar

thx a lot

_________________
regards,
HaWe aka Ford
#define S sqrt(t+2*i*i)<2
#define F(a,b) for(a=0;a<b;++a)

Wed Jul 30, 2008 4:03 am
Rookie

Joined: Tue Aug 12, 2008 11:06 pm
Posts: 2
Re: needed: exponential function with any a real (float) base
Does RobotC have an e^x function? Isn't exp(x) really 10^x in RobotC?

Tue Aug 12, 2008 11:09 pm
Guru

Joined: Sat Mar 01, 2008 12:52 pm
Posts: 1030
Re: needed: exponential function with any a real (float) base
 erabenda wrote:Does RobotC have an e^x function? Isn't exp(x) really 10^x in RobotC?

shock:
I never doubted that exp(x) = e^x !

(edit:)
but as Dick Swan wrote and as I could check,
exp(x) = e^x and log(x)=ln(x)
as it was supposed to be.

_________________
regards,
HaWe aka Ford
#define S sqrt(t+2*i*i)<2
#define F(a,b) for(a=0;a<b;++a)

Last edited by Ford Prefect on Wed Aug 13, 2008 9:26 am, edited 1 time in total.

Wed Aug 13, 2008 2:57 am
Rookie

Joined: Tue Aug 12, 2008 11:06 pm
Posts: 2
Re: needed: exponential function with any a real (float) base
Thanks for the quick response! I thought I had read somewhere that the exp(x) was something other than e^x.

Wed Aug 13, 2008 9:26 am
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