t=linspace(-10,10,200);
k=1

k =

     1

x(1:100)=(-1/(2*sqrt(k)))*exp(sqrt(k)*t(1:100));
x(101:200)=(-1/(2*sqrt(k)))*exp(-sqrt(k)*t(101:200));
plot(t,x)
hold on
k=4

k =

     4

x(1:100)=(-1/(2*sqrt(k)))*exp(sqrt(k)*t(1:100));
x(101:200)=(-1/(2*sqrt(k)))*exp(-sqrt(k)*t(101:200));
plot(t,x)
k=10

k =

    10

x(1:100)=(-1/(2*sqrt(k)))*exp(sqrt(k)*t(1:100));
x(101:200)=(-1/(2*sqrt(k)))*exp(-sqrt(k)*t(101:200));
plot(t,x)
diary off