# How can I plot two functions in the same graph?

935 views (last 30 days)
Íris on 17 Sep 2014
I have to show that the functions f(x)=x/10 and g(x)=cos(x) intersect at least twice the range [-3,3]. Can anybody help me?
Raul Galdeano Pazos on 19 Feb 2022
Hi Íris!
In my view, there are two ways of tackling this problem. Firstly, doing this;
%------------------------------------------------------------------------------------------------------------------------------------------------------------
x = -3:0.1:3;
y1 = x/10;
y2 = cos(x);
%Firstly, just plot one single function;
figure(1)
plot(x,y1,"r-","Linewidth",2);
hold on
%Then, plot the rest of the functions;
plot(x,y2,"b-","Linewidth",2);
I think this way of plotting, despite having more lines of code, works too!
R.G.

Mischa Kim on 17 Sep 2014
Iris, use
x = -3:0.1:3;
f = x./10;
g = cos(x);
plot(x,f,x,g)
rockstar49 on 25 Oct 2020
Using this way to plot multiple functions, how can you use the legend on function to differenitate between each line?

Aayushii Goswami on 21 Oct 2017
I have to sketch the graph of y^2=8x and x^2=8y on the same axis system and shade the bounded area.can anyone pls help me?

Realeboha Ramoeletsi on 9 Jul 2021
t=linspace(0.2,50,100);
alpha=0.5;
c1=2;
r=0.2;
sigma=0.25;
Nt=1600;
Ns=160;
Smax=20;
Smin=0;
T=1.;
E=10;
dt=(T/Nt);
ds=(Smax-Smin)/Ns;
V(1:Ns+1,1:Nt+1)=0.0;
S=Smin+(0:Ns)*ds;
tau=(0:Nt)*dt;
V(1:Ns+1,1)=max(S-E,0);
V(1,1:Nt+1)=0;
V(Ns+1,1:Nt+1)=Smax-E*exp(-r*tau);
y1=C(t,alpha,c1);
figure(1)
plot (S,V(:,1),'r-',S,V(:,round(Nt/2)),'g-',S,V(:,Nt+1),'b-');
plot(t,y1,'-r')
xlabel('S')
ylabel('V(S,tau)')
for j=1:Nt
for n=2:Ns
V(n,j+1)=0.5*dt*(sigma*sigma*n*n-r*n)*V(n-1,j)+(1-dt*(sigma*sigma*n*n+r))*V(n,j)+0.5*dt*(sigma*sigma*n*n+r*n)*V(n+1,j);
end
end
function y=C(t,alpha,c1)
if ~all(t>0)
error(" t values must be positive")
end
if alpha<0 || alpha>1
error("alpha must be in the range (0,1) excluding both ends")
end
y=c1*t.^(alpha-1)./gamma(alpha);
end
i have two functions y and V and i did plot them separately one on its plot, so i am having a problem on ploting the same fuctions in one figure, can someone help me please. thank you.
i have attached .m file

Nilankan Pal on 13 May 2021
x = -3:0.1:3;
f = x./10;
g = cos(x);
plot(x,f,x,g)