Plot 2 Tangent Lines in a function

Im having problems while doing a function because I want to plot 2 tangent lines in x=1 and x=5 but Im not sure how to plot it, this is my current code

figure()
yline(0)
xline(0)
hold on
syms f(x)
f=15000*exp(x)^(-.6286*x)

f = 

diff(f)

ans = 

fplot (x,f, [0,10])

Answer 1

[Drishan Poovaya]

Hi

Please have a look at the code snippet below. It calculates the tanget at points 1 and 5 and plots the tangents. Keep in mind that the tangent at 5 overlaps with your xline(0) hence it is not visually distinguishable

figure()
yline(0)
xline(0)
hold on
syms f(x)
f=15000*exp(x)^(-.6286*x);
fplot (x,f, [0,10])
dy(x)=diff(f,x);

% y = mx + c
% at 1
m = subs(dy,x,1);
m = double(m);
y = double(subs(f,x,1));
c = y - m*1;
syms t(x)
t = m*x + c;
fplot (x,t, [0,10])


% at 5
m = subs(dy,x,5);
m = double(m);
y = double(subs(f,x,5));
c = y - m*5;
syms t(x)
t = m*x + c;
fplot (x,t, [0,10])