How to draw tangent line at specified points in a curve
조회 수: 18 (최근 30일)
이전 댓글 표시
I am having a an array of points x,y and respective angles at those specified points. I want to plot a tangent line at those points, i am unable to figure out how to proceed.
As shown in command window 1st column contains x points , 2nd column contains y points and 3rd column the respective tangent angle. Figure 1 is plot between x and y points. Thanking you.
Regards,
Mrinal
댓글 수: 1
Ngo Nguyen
2013년 9월 18일
편집: Ngo Nguyen
2013년 9월 18일
If you have the coordinates M(x,y) , so you can find the slope m:
m= -(x - x0) / (y - y0) , (x0,y0) is the center of the circle
After that, you can plot the tangent line at M y = m*(x - x0) + y0 plot(x,y)
답변 (1개)
Image Analyst
2013년 9월 18일
편집: Image Analyst
2013년 9월 18일
You have to figure out the slope at each point, then decide where the endpoints of the tangent line should be, then call line([x1, x2], [y1, y2], 'Color', 'b'). As a rough guess you can probably just say the slope at xn,yn is
slope = (y(n+1)-y(n-1)) / (x(n+1) - x(n-1));
or just get the slope from the tangent angle that you already have. Then the formula for the line is (from high school algebra)
y = slope * (x - x(n)) + y(n);
You just need to figure out how far away from x(n) do you want your endpoints of your tangent line segment. I believe you can just use xLeft = min(x) and xRight = max(x) if you just want the line to go everywhere and not see the endpoints lie inside the plot.
참고 항목
제품
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!