Hi, I am working on Some code I could find the Function for Log but not for any Antilog option.

The x=log10(1000); 10^x option is not working it throws an Error.

Nor loginv.

Please if you have any options do reply. Thanks in Advance!!

[Cam Salzberger]

loginv is not a built-in function as far as I am aware. When I run:

x = log10(1000);
10^x

I get 1000 back out as expected. What are you getting?

If you want to provide an array of values to log10, then get them back from a power function, use 10.^x instead of 10^x.

Answer 1

[John D'Errico]

Of course there is no loginv, since raising something to a power is the inverse of the log function. Powers already exist in MATLAB so there is no need for a loginv function. (I suppose it might be nice for completeness to have that, but you can always write a loginv function yourself, if that "lack" bothers you.)

10^x is an error, BECAUSE x is not a scalar. If you need to exponentiate an array or a vector, then use 10.^x.

So the inverse of log (the natural logarithm) is the function exp.

The inverse of log10 is 10.^x.

The inverse of log2 is 2.^x.

Answer 2

[aaru sri]

if i have y=exp(i*2*pi*x) and i want to find x how i cn do it

[Steven Lord]

Take the log of both sides then divide.

[Bruno Luong]

If you are lucky, then steve's method might work, otherwise you'll only find x+k with k arbitrary integer, and there are a lot of them out there.

[aaru sri]

i have taken log on both sides but the value of x is not same as previous one

asdf=exp(i*2*pi*bbbb);

asdff=log(asdf); %value

asdf1=i*2*pi*bbbb; %value same as asdff

asdf3=asdff./i*2*pi; %value of bbbb is not same as asdf3

[Bruno Luong]

Check at least your parenthesis

[aaru sri]

i didnt get u

[Bruno Luong]

"parenthesis": (...)

>> 1/2*3

ans =

    1.5000

>> 1/(2*3)

ans =

    0.1667

>> 

Answer 3

[aaru sri]

thnk u so much my prob is solved