how to solve this
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p=[101.3 106.6 109.4 114.7 116.9 118.2 123.7];
v=[1.69 3.67 4.37 5.45 5.84 6.05 6.90];
% 4 ways for interpolation
lin=interp1(v,p,5,'linear')
m=interp1(v,p,5,'makima')
sp=interp1(v,p,5,'spline')
n=interp1(v,p,5,'nearest')
% Display a graph of speed versus pressure, the graph will include the given measurements
as well as the results obtained using 4 methods interpolation.
Mark with a red asterisk the points where the speed is 5 [m/s.]
* Labels must be added to the axes, legend, grid lines and title.
采纳的回答
You almost got it. Maybe you just needed to read the manual some more and understand what is x and what is y.
p=[101.3 106.6 109.4 114.7 116.9 118.2 123.7];
v=[1.69 3.67 4.37 5.45 5.84 6.05 6.90];
plot(p, v, 'b.-', 'LineWidth', 2, 'MarkerSize', 20);
grid on;
xlabel('Pressure');
ylabel('Velocity');
% 4 ways for interpolation
xq = linspace(min(p), max(p), 500);
lin=interp1(p, v, xq,'linear') ;
m=interp1(p, v, xq,'makima');
sp=interp1(p, v, xq,'spline') ;
n=interp1(p, v, xq,'nearest');
% Find where speed is closest to 5
[value, index] = min(abs(lin - 5)) % Value is how far away from 5 the data point is.
x5 = xq(index)
y5 = lin(index)
hold on;
yline(5, 'Color', 'r') % Horizontal red line at 5.
xline(x5, 'Color', 'r') % Horizontal red line at 5.
% Plot a red asterisk at the point closest to y=5
plot(x5, y5, 'r*', 'MarkerSize', 30, 'LineWidth', 2)
Go ahead and add the rest, like legend, title, etc.
更多回答（1 个）
Walter Roberson
2023-1-19
When you call plot, you can use
plot(x1, y1, x2, y2, x3, y3, ...)
where x1 and x2 and x3 and so on might happen to all be the same.
For the part about red: see https://www.mathworks.com/help/matlab/creating_plots/create-line-plot-with-markers.html#bvcbmlx-1
4 个评论
daniel
2023-1-19
daniel
2023-1-19
编辑：Walter Roberson
2023-1-19
daniel
2023-1-19
Walter Roberson
2023-1-19
plot(v,p,lin,m,sp,n,'r*',5)
That code asks to use v as the first independent variable, and plot p as dependent on it. And then to take lin as the next independent variable and plot m as depedent on it.
Contrast to
plot(v, p, v, lin, v, ...)
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