# write a function called tri_area returns the area of a triangle with base b and height h

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Andrew Ayman on 9 Apr 2020
Commented: Noor Fatima on 5 Feb 2023
hello this is my function code and command window code and there is a message of invalid expression at line 2 and i dont know what is the wrong can anyone help me
function [area] = tri_area([b,h]);
tri_area([b,h])=(0.5)*(b)*(h)
area=tri_area([b,h])
end
%command window
area = tri_area[3,2])
Noor Fatima on 5 Feb 2023
Thanku Walter roberson

Torsten on 9 Apr 2020
Edited: darova on 9 Apr 2020
function area = tri_area(b,h)
area = 0.5*b*h;
end
From the command window
A = tri_area(3,2)
Walter Roberson on 26 Dec 2022
When you use the debugger and format long g then what are some sample inputs, and what is the calculated output, and what does the grading program say that the output should be?

Imane Tahar on 19 Nov 2020
function area = tri_area(b,h)
area = (b*h)/2
end

Siya Desai on 4 Apr 2021
Edited: Siya Desai on 4 Apr 2021
function
function [area] = tri_area (b,h)
tri_area = (0.5)*(b)*(h)
tri_area(2,3) %any random input
Walter Roberson on 4 Apr 2021
result = tri_area(2,3) %any random input
tri_area = 3
Output argument "area" (and maybe others) not assigned during call to "solution>tri_area".
function [area] = tri_area (b,h)
tri_area = (0.5)*(b)*(h)
end

Pelden Chodon on 27 May 2021
function [area, tri_area] = tri_area(b,h) ;
area = (0.5)*(b)*(h);
v = area(:);
tri_area = sum(v);
end
% Test that your function runs as expected before pressing Submit
[area, tri_area] = tri_area(2,3)
DGM on 4 Feb 2023
You're declaring a variable with the same name as the function you're calling. This will either throw an error or silently cause other errors, depending on where you put the function.
For scalar inputs, summing area serves no purpose. For nonscalar inputs, the results are either wrong, or will throw an error.
% summing a scalar accomplishes nothing
[allareas totalarea] = tri_area(2,3)
allareas = 3
totalarea = 3
% some nonscalar inputs return the wrong results
[allareas totalarea] = tri_area([2 2; 2 2],[3 3; 3 3])
allareas = 2×2
6 6 6 6
totalarea = 24
% some nonscalar inputs return the wrong number of wrong results
[allareas totalarea] = tri_area([2 2],[3;3])
allareas = 6
totalarea = 6
% some nonscalar inputs fail completely
[allareas totalarea] = tri_area([2 2],[3 3])
Error using *
Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To operate on each element of the matrix
individually, use TIMES (.*) for elementwise multiplication.

Error in solution>tri_area (line 10)
allareas = (0.5)*(b)*(h); % these parentheses serve no purpose
function [allareas, totalarea] = tri_area(b,h)
allareas = (0.5)*(b)*(h); % these parentheses don't do anything
v = allareas(:);
totalarea = sum(v);
end
As this is all largely copy-pasted from other bad answers posted above, I should point out that much of these problems were already openly explained before you posted this. See also: function, array vs matrix operations