charting in-between values

i like to chart in-between values of a given chart.
e.g.
a chart has two given points on the x and y-axis:1,1 and
3,3. Now i like to have the y-value when i add an extra x-
value e.g. 2. Can excel do this for me?

On Thu, 16 Oct 2003 11:23:55 -0700, jan wrote:

i like to chart in-between values of a given chart.
e.g.
a chart has two given points on the x and y-axis:1,1 and
3,3. Now i like to have the y-value when i add an extra x-
value e.g. 2. Can excel do this for me?

I suspect you may have just posted a very similar question under an =

" name. I just posted one potential=
=

answer there.

-- =

Dave
dvt at psu dot edu

How's your math?
A straight line has the formula y = mx + b where m is the slope, b the
intercept
With two known point (x1,y1) and (x2,y2), m = (y2-y1)/(x2-x1)
So b = y1 - mx1
Now we know m and b
For the unknown point (x3,y3), we can find y3 = m*x3 - b

Of course you could use SLOPE and INTERCEPT to find m and b but this would
be overkill with just 2 known point,
Bernard
www.stfx.ca/people/bliengme

"jan" wrote in message
...
i like to chart in-between values of a given chart.
e.g.
a chart has two given points on the x and y-axis:1,1 and
3,3. Now i like to have the y-value when i add an extra x-
value e.g. 2. Can excel do this for me?