I have data point which fits the line y=mx+c ? How can I write code for this?

I have data point which fits the line y=mx+c ? How can I write code for this?

Answer 1

[sixwwwwww]

write as follow

    x = 0:100;
    m = 3;
    c = 4;
    y = m * x + c;
    plot(x, y)

[RS]

If I dont know value of m and c so how can I fit data point using y=mx+c

[sixwwwwww]

then use curve fitting tool. see

doc cftool

if you have x and y given then use directly

cftool(x, y)

[RS]

ok but I want to plot a line y=x in this and want to find out value of c in my output and angle between two lines y=mx and y=mx+c.

[sixwwwwww]

if values of x and y are given then you can do as follow. I suppose you x and y vectors then:

m = (y(2) - y(1)) / (x(2) - x(1));
c = x(1) - m * y(1);

[RS]

How can I write for any arbitrary data set of x and y, first fit as y=mx+c and from this fit find c and then with the help of other line y=x it will find angle between two lines ?

[sixwwwwww]

The problem is that in order to plot the equation you need to have 3 known values and one unknown value because there 4 values in equation x, y, m and c. So you should atleast have three values or if you just plot some random values of x and y and then want to find m and c then using cftool is the best option

[sixwwwwww]

If you are given values of x and y then you can compute m and c as follow:

fitvars = polyfit(x, y, 1);
m = fitvars(1);
c = fitvars(2);

Answer 2

[chitresh]

>>syms x y m c

>> solve(' y = m * x + c')

i think this gone solve your question, if it is solved accept the answer

[RS]

I am getting value of x here after giving value of m, y and c but in problem I don't know value of m and c only x and y is known to me.

How can I write for line passes through if x and y are given and find slope and c?

[chitresh]

dear here m and c where constant, by substituting the value of x and y you get your answer and you can plot your lines too for this plz go through linear programming mathematics here is a link for this

http://www.teacherschoice.com.au/maths_library/functions/y_=_mx_+_c.htm

[chitresh]

if you done with your question, mark the answer accepted

[Image Analyst]

And officially Accept answers in more than 30 other questions that you've asked.