- #1

CMJ96

- 50

- 0

## Homework Statement

s=0.140406704

**2. Relevant equation**

## The Attempt at a Solution

So I converted the ODE into the following two equations

$$\frac{dx_1}{dt}=x_2$$

$$\frac{dx_2}{dt}=x_1- \alpha sin(x_2)$$

I have done the following with the program so far, I came to a halt because I am not sure how to define k1 and k2 with functions of 3 variables, also I find it a little confusing that there is a time-step despite there being no t's in the functions?

program ab2

implicit none

integer :: i,n

real :: t,x1,x2,func1,func2,h, t0, x10,x20,s,k11,k12,k22,k21

a=0.5

h=0.01

t0=0

t=t0

s=0.140406704

x10=s

x20=-s

x1=x10

x2=x20

end program

function func1(x1,x2,t)

real :: func1,x1,t,x2

func1= x2

end function func1

function func2(x1,x2,t)

real :: func2,x1,x2,t,a

func2= x1-a*sin(x2)

end function func2