Can someone tell me how will I be able to remove the error in this script? I have already the answers but it says error.

(For reference of the first photo)

[KSSV]

Copy and paste the code here. Image snippet will not help us to help you.

Any ways, varible f is now shown here. Error is with f.

[Torsten]

@Neil Allen

I think the assignment didn't want you to calculate all the quantities with pencil and paper and just insert the results into the code.

E.g. yprime should most probably be diff(f,x) and not 3*x^2-3.

[Neil Allen]

@KSSV @Torsten

I have already managed on fixing it. The problem now it says is that the "variable yprime must be of data type symfun. It is currently of type sym. Check where the variable is assigned a value." It says the same on the Slope, tangent and normal line. I suppose that the tangent line should be slanted but it just go horizontally.

Here is the code and given function:

f(x)= x^3-3x+2

% This program computes for the Tangent Line / Normal Line of a curve % about a given point
                   %define x for symbolic processing
syms x 
%IDENTIFY the function f(x)
f(x) = (x^3-3*x+2);

%DETERMINE the point of tangency (This will be a random point)
x0=randi([-5,5])

x0 = 1

%SOLVE for the Ordinate of the point of tangency
y0=f(x0);  %Evaluate y given value fo x

%FIND the slope function
yprime =diff(f(x0));               %Solve for the first derivative

%Determine the slope at the given x0
m= yprime;         %Evaluate the slope

%Solve the equation of the tangent line
ytangent= m*(x-x0)+f(x0);

%Solve the Equation of the normal line
ynormal= (-1/yprime)*(x-x0)+f(x0);

%DISPLAYING RESULTS
fprintf('The tangent line to f(x)=%s at (%.2f, %.2f) is y = %s \n',string(f(x)),x0,y0, string(ytangent))

The tangent line to f(x)=x^3 - 3*x + 2 at (1.00, 0.00) is y = 0 

fprintf('The normal line to f(x)=%s at (%.2f, %.2f) is y = %s \n',string(f(x)),x0,y0, string(ynormal))

The normal line to f(x)=x^3 - 3*x + 2 at (1.00, 0.00) is y = -Inf*(x - 1) 

%PLOTTING
g1=ezplot(f,[-15,15]);
set(g1,'color','b')
grid on
hold on
plot(x0,y0,'r*')
text(x0+1,y0,"Point of Tangency")
g2=ezplot(ytangent,[-15,15]);
text(5,5,["y(Tangent)=", string(ytangent)])
pause(1)
set(g2,'color','m')
pause(1)
g3=ezplot(ynormal,[-15,15]);
text(3,3,["y(Normal)=", string(ynormal)])
set(g3,'color','c');
title("Tangent Line and Normal Line")

[Torsten]

syms x 
%IDENTIFY the function f(x)
f = x^3-3*x+2

f = 

%DETERMINE the point of tangency (This will be a random point)
x0=randi([-5,5])

x0 = 0

%SOLVE for the Ordinate of the point of tangency
y0=subs(f,x0)  %Evaluate y given value fo x

y0 = 

2

%FIND the slope function
yprime =diff(f,x)               %Solve for the first derivative

yprime = 

%Determine the slope at the given x0
m=subs(yprime,x,x0)        %Evaluate the slope

m = 

%Solve the equation of the tangent line
ytangent= m*(x-x0)+y0

ytangent = 

%Solve the Equation of the normal line
ynormal= (-1/m)*(x-x0)+y0

ynormal = 

%DISPLAYING RESULTS
fprintf('The tangent line to f(x)=%s at (%.2f, %.2f) is y = %s \n',string(f),x0,y0, string(ytangent))

The tangent line to f(x)=x^3 - 3*x + 2 at (0.00, 2.00) is y = 2 - 3*x 

fprintf('The normal line to f(x)=%s at (%.2f, %.2f) is y = %s \n',string(f),x0,y0, string(ynormal))

The normal line to f(x)=x^3 - 3*x + 2 at (0.00, 2.00) is y = x/3 + 2 

[Neil Allen]

@Torsten

Thank you so much! :D