how to draw the line of known slope and intercept
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Hello, I have a line which is in the form ax+by+c=0, with a,b and c known. In addition, I have a specific (x,y) point known, and the line should pass through it. How can I draw this line in matlab?
采纳的回答
Walter Roberson
2011-5-22
If a*x + b*y + c = 0 then b*y = - c - a*x and then provided b is non-zero, y = -c/b - a/b * x
Then if the line is to pass through a specific (x,y) the only thing you have to worry about is ensuring that the range of x you plot includes the specific x .
For example,
x = 15:41;
y = -19/11 - (-3/2)/11 * x;
plot(x,y)
更多回答（4 个）
Daniel Shub
2011-5-22
I like refline
doc refline
Matt Fig
2011-5-22
You could also do it using MATLAB's polynomial functions...
% Data
a = -2;
b = 3;
c = 8;
x = 3;
y = -2/3;
% Now the plotting.
pp = [-a,-c]/b; % Polynomial as MATLAB likes it.
X = linspace(x-1,x+1); % Where to plot the line...
pv = polyval(pp,X); % Evaluate the polynomial.
plot(X,pv,'-b',x,y,'*r')
noor
2011-6-17
0 个投票
Hello, I'd like to know the slope for image 2D array. Need I draw line of known the slope? Thanks a lot
1 个评论
Walter Roberson
2011-6-17
slope of a 2D array is a completely different concept. Please open a new Question for this, if you have not already done so.
Amr Aboughazala
2022-5-6
0 个投票
for a line ax + by - c
you can draw the line using the coefficients as follows,
y = -(a*x+c) / b
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