Help with logarithmic equation formula

[coachrivas]

I have a question. I am trying to figure out how to input this equation in a cell of excel. y= -23.78ln(x)+514.04


x is 1500


Any help would be greatly appreciated!


If this helps, http://i42.tinypic.com/2uifyiw.jpg


Im trying to figure out how many meters per minute 1500m is according to my logarithmic graph.


Thanks!!

 

[NARAYANK991]

Hi ,


If you would like to plot this graph in Excel , then the best way would be to have a range of your X-values , and use a formula for the Y-values.


Suppose you wish to have X-values 50 metres apart.


Let us say we start the X-values from cell A5. Type in 0 in cell A5 ; type in 50 in cell A6 ; select both these cells and drag down till you reach the upper limit of your X-values , say 5000. You now have your X-values from 0 ( in cell A5 ) till 5000 ( in cell A105 ).


In cell B5 enter the following formula :


=-23.78*LN(A5)+514.04


Copy this formula down till B105.


In cell B5 you will have an error value , which means this function is not defined for an X-value of 0.


Ignoring this one value , you can use the other values from X = 50 till X= 5000.


Plot the chart , and adjust the minimum value for the Y-axis to 300 so that you get a more detailed graph.


Narayan