Using loglog for plotting a logarithmic graph

Question

Viran Silva 2014-11-22

评论： Youssef Khmou 2014-11-22

Hello.

Part of my 2 part assignment is to complete a loglog graph plot of a certain function, and it happens to be a complicated function;

96818.90647*sqrt(55327.86446+((19.62x)/25.88677539))*log(1+(x/73000))

And the x values I have to plot the function against the x values is in the range of x=10-19700.

The code I have written so far is:

>> x = 10:19700

>> loglog([x],[96818.90647*sqrt(55327.86446+((19.62x)/25.88677539))*log(1+(x/73000))])

But MatLab keeps giving me the unexpected Matlab expression - is there anything that I am doing wrong with my code so far?

All I am trying to do is plot a graph of these x values against the function, and I am very new to Matlab - so any help is greatly appreciated.

Thank you in advance.

- Viran

Answer 1

Youssef Khmou 2014-11-22

You have to use element wise operator ( . before any operator sign) :

   x = 10:19700;
   y=96818.90647.*sqrt(55327.86446+((19.62*x)/25.88677539)).*log(1+(x/73000));
   loglog(x,y)

Viran Silva 2014-11-22

编辑：Viran Silva 2014-11-22

Okay, why did that work when you added periods to it?

Youssef Khmou 2014-11-22

no periods are added. operations of vectors/matrices are not performed unless they compatible in size.