how to fix this error

clc;
% Data Taken from given projectile phots and vedios
%Flight time(seconds) is calculated using  vedio real time
% Angle(degree) is  measured using photo when projectile lanching
% height(m) is calculated as disatnce between ground and projectile 
% Flight time = Tf   
% Angle = theta
Tf=20;
theta=60;
height=5000;
g=9.81;
velocity=(g*Tf)/(2*sind(theta))

velocity = 113.2761

%1feet=0.3048m
figure;
hold on;
e=1;
A=[0.3048];
B=[1000:100:10000];
C=A*B;
for height= [5000:100:30000]
  for range=C
     [maxHeight(e),horDist(e)]=projMotion(velocity,height,range);
     e=e+1;
  end
end

Angle = 3×1

-86.5115 -4.8298 4.8051

Vyi = 3×1

-113.0662 -9.5373 9.4888

Vxi = 3×1

6.8927 112.8739 112.8780

maxHeight = 3×1

1.0e+03 * 5.6516 5.0046 5.0046

tmax = 1×3

0 0 2.7003

horDist = 304.8000

d = 3×1

5000 5000 5000

Hittingvelocity = 3×3

113.2761 113.2761 139.7259 113.2761 113.2761 118.4840 113.2761 113.2761 114.1511

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

xlabel('Horizontal Distance (m)');
ylabel('Vertical Distance (m)');
title('Projectile Motion');
function [maxHeight,horDist] = projMotion(velocity,height,range)
 
% finding angle
        g=9.81;
        a=1;
        b=height/range;
        c=0;
        d=(-g*range)/(2*velocity.^2);
        p=[a b c d];
        r=roots(p);
        Angle=atand(r)
            for angle=[Angle]
                Vyi=velocity*sind(angle)
                Vxi=velocity*cosd(angle)
                maxHeight=height+Vyi.^2/g-0.5*(Vyi.^2/g)
                tmax=range/Vxi
                    for t=[0:0.001:tmax]
                        horDist=tmax*Vxi
                        d=height+Vyi*t-.5*g*t.^2
                        plot(Vxi*t,d)
                        hold on
                        Hittingvelocity=sqrt((velocity*sind(angle)-g*tmax).^2+(velocity*cosd(angle)).^2)
                    end
            end
end

Answer 1

[Hussain Alsalman]

I need to find out projectile angle when velocity,intial height,range given.

please help me to sort out this error

Answer 2

[Walter Roberson]

        p=[a b c d];

vector length 4

        r=roots(p);

roots() returns a column vector of length one less than the length of the vector, so 3x1 in this case

        Angle=atand(r)

atand of a column vector is a column vector

            for angle=[Angle]

"for" loops over the *columns" of the right hand side. It is not going to iterate the three roots one at a time: it is going to iterate once with angle set to the three roots as a vector.

[Hussain Alsalman]

do i need to angle output as a column vector

[Walter Roberson]

You already have it as a column vector, and that is what is leading to problems. Your for angle loop needs the right hand side to be a row vector.