Help locating a Math Equation to fit this curve

• Calculus
• ikihi

ikihi

The concentration is the Y axis, and the values are the x axis. What is the equation for finding a target value on a curve between set of points?

That completely depends on the curve. Since you have not provided any more information than ”curve”, nobody can say.

ikihi said:
The concentration is the Y axis, and the values are the x axis. What is the equation for finding a target value on a curve between set of points?
That looks a bit like a square root function.
Swap the x and y axes, and it becomes a parabola.
It takes three known points to fit a parabola, but you only have two.
The best you can do with two points is a straight line.

Log-Log graphs are good for power functions. Maybe if you plot Log(x) against Log(y) to get a straight line, it would make interpolation easier, but still unreliable. That assumes there is no data less than or equal to zero on the x or y axis.

ikihi said:
The concentration is the Y axis, and the values are the x axis. What is the equation for finding a target value on a curve between set of points?
View attachment 335714
I have not read other responses yet and have not picked at this one yet, but the curve drawn appears like part of a circle. Can you work that way with your example?

Also, the description for your graph is incomplete. WHAT is the x-axis? What are those "values" supposed to mean?

ikihi
We cannot be sure what points we see accented on your graph. What are the ordered pair of those points accented in the big red dots?

edit: If we try to estimate to read your two points they may be (6.9 , 0.0093) and (4.8, 0.0041) .

If we guess that you have attempted to fit your scale numberings to the points, as off as they appear, these might be (4.8, 0.0040) and (7.0, 0.0080).
What ARE the two given points?

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I changed my mind. I do not like the idea of fitting those only two points to a circle. Better for some square root function or logarithmic function. Still we no know your actual given points.

To be honest, neither the square root function norbthe circle seem like good firs to me. This entire discussion just accentuates what I already said in #2. There is way too little information in the OP to make anything but guesswork.

Orodruin said:
There is way too little information in the OP to make anything but guesswork.
Concentration suggests chemistry, which suggests adding exponential decay to the list of possible functions.

Like a good mystery, we need a couple of more data points, and units for the axes.