Any suggestion on how to solve this problem using Matlab?

How plot the function in the picture by using Matlab?

[Geoff Hayes]

James - what have you tried so far? This seems like homework so please post what you have attempted and discuss what is causing errors or confusion (for you).

Answer 1

[Yasasvi Harish Kumar]

The below code should be able to plot the required.

m = 25;

mu = 0.55;

g = 9.81;

for t = 0:90

F(t+1) = mu*m*g/(cosd(t) + mu*sind(t));

theta(t+1) = t;

end

plot(theta,F)

Answer 2

[Stephen23]

I know this is homework, but someone needs to show that it is a waste time writing loops, it is much better to write simple vectorized code:

a.1.

>> mu = 0.55;
>> g  = 9.81; % m/s/s
>> m  = 25;   % kg
>> theta = 0:0.5:90;
>> F = mu*m*g./(cosd(theta) + mu*sind(theta));
>> plot(theta,F)

For the next parts you should define a simple anonymous function:

>> fun = @(t) mu*m*g./(cosd(t) + mu*sind(t));

a.2.

>> t150 = fzero(@(t)fun(t)-150,[40,100])
t150 =  66.818
>> fun(t150)
ans =  150

b.

>> tmin = fminsearch(fun,50)
tmin =  28.810
>> fun(tmin)
ans =  118.19

I am sure that you can manage the last tiny bit yourself.