i need to plot this function and determine the exact valuse of the derrivative at x=1

F(x)= 2x^3-3x+4 for the interval [-2,2]

[Amit]

what is the question? Are you asking how to use plot function?

[adriana resendez]

yes

Answer 1

[Eduardo Márquez]

Check help symbolic, if blue letter show it's oknd run:

% help symbolic

clear all; clc; close all;

syms fx x                 % Declare syms functions f(x) and x

fx = 2*(x^3) - 3*x + 4;   % Funtion f(x)

Dfx = diff(fx,x);         % f'(x)

xx=-2:.1:2;

subv = subs(fx,x,1);      % Evalue f(x), x=1;

dfx1 = double(subv)       % Back to double the answer

ez1=ezplot(fx,xx);

hold on

ez2=plot(1,dfx1,'ro');    % Show the point

[adriana resendez]

let me check it out thank you

[Eduardo Márquez]

Check and modific the line

subv = subs(fx,x,1);      % Evalue f(x), x=1;

by

subv = subs(Dfx,x,1);      % Evalue f'(x), x=1;

Sorry

Final code is:

% help symbolic

clear all; clc; close all;

syms fx x

fx = 2*(x^3) - 3*x + 4;

Dfx = diff(fx,x);

xx=-2:.1:2;

subv = subs(fx,x,1);

dfx1 = double(subv)

ez1=ezplot(fx,xx);

hold on

ez2=ezplot(Dfx,xx);

set(ez2,'color',[1 0 0])

ez3=plot(1,dfx1,'ro');

[adriana resendez]

mkay