## Need solution to this problem please

## Need solution to this problem please

(OP)

program pisarchik

implicit none

real*8 t,tstep,y(5)

integer N,i,j,nsteps

N=5;nsteps=0.1;y(1)=0.6;y(2)=0.0;y(3)=0.6;y(4)=0.0;y(5)=0.0

open(6,file='p.dat')

write(6,*)0,Y(1),Y(2),Y(3),Y(4),Y(5)

do J = 1,nsteps

t = j*tstep

call rk4(t,y,tstep,N)

write(6,*)0,Y(1),Y(2),Y(3),Y(4),Y(5)

enddo

stop

end

subroutine rk4(t,y,tstep,N)

implicit none

real*8 deriv,h,t,tstep,y(5)

real*8 k1(5),k2(5),k3(5),k4(5),temp1(5),temp2(5),temp3(5)

real temp4(5),temp5(5)

integer i,N

h = tstep/2.0

do i = 1,N

k1(i) =tstep*deriv(t,y,i)

temp1(i) = y(i) + 0.5*k1(i)

enddo

do 20 i = 1,N

k2(i) =tstep*deriv(t+h,temp1,i)

temp2(i) = y(i) + 0.5*k2(i)

20 continue

do 30 i = 1,N

k2(i) =tstep*deriv(t+h,temp2,i)

temp3(i) = y(i) + k3(i)

30 continue

do 40 i = 1,N

k4(i) =tstep*deriv(t+tstep,temp3,i)

y(i) = y(i) + k1(i) + 2.0*(k2(i) + k3(i) + k4(i))/6.0

40 continue

return

end

function(t,temp,i)

implicit none

real*8 deriv,t,temp(5)

integer i

if(i.eq.1)deriv = temp(2)

if(i.eq.2)deriv = -0.4*temp(2)+(0.25+temp(5)) - 0.5*temp(1)**3

& - delta*temp(1)*temp(3)**2

if(i.eq.3)deriv = temp(4)

if(i.eq.4)deriv = -0.4*temp(4)+0.25*temp(3) - 0.5*temp(3)**3

& - delta*(temp(1)**2)*temp(3)

if(i.eq.5)deriv = 2*3.14*sqrt((0.25*0.8)**2-temp(5)**2)

return

end

System to be solve as an example is

Want δ to vary from 0.3 to 0.5 and

1) plot x1 versus δ

2) x3 versus δ

implicit none

real*8 t,tstep,y(5)

integer N,i,j,nsteps

N=5;nsteps=0.1;y(1)=0.6;y(2)=0.0;y(3)=0.6;y(4)=0.0;y(5)=0.0

open(6,file='p.dat')

write(6,*)0,Y(1),Y(2),Y(3),Y(4),Y(5)

do J = 1,nsteps

t = j*tstep

call rk4(t,y,tstep,N)

write(6,*)0,Y(1),Y(2),Y(3),Y(4),Y(5)

enddo

stop

end

subroutine rk4(t,y,tstep,N)

implicit none

real*8 deriv,h,t,tstep,y(5)

real*8 k1(5),k2(5),k3(5),k4(5),temp1(5),temp2(5),temp3(5)

real temp4(5),temp5(5)

integer i,N

h = tstep/2.0

do i = 1,N

k1(i) =tstep*deriv(t,y,i)

temp1(i) = y(i) + 0.5*k1(i)

enddo

do 20 i = 1,N

k2(i) =tstep*deriv(t+h,temp1,i)

temp2(i) = y(i) + 0.5*k2(i)

20 continue

do 30 i = 1,N

k2(i) =tstep*deriv(t+h,temp2,i)

temp3(i) = y(i) + k3(i)

30 continue

do 40 i = 1,N

k4(i) =tstep*deriv(t+tstep,temp3,i)

y(i) = y(i) + k1(i) + 2.0*(k2(i) + k3(i) + k4(i))/6.0

40 continue

return

end

function(t,temp,i)

implicit none

real*8 deriv,t,temp(5)

integer i

if(i.eq.1)deriv = temp(2)

if(i.eq.2)deriv = -0.4*temp(2)+(0.25+temp(5)) - 0.5*temp(1)**3

& - delta*temp(1)*temp(3)**2

if(i.eq.3)deriv = temp(4)

if(i.eq.4)deriv = -0.4*temp(4)+0.25*temp(3) - 0.5*temp(3)**3

& - delta*(temp(1)**2)*temp(3)

if(i.eq.5)deriv = 2*3.14*sqrt((0.25*0.8)**2-temp(5)**2)

return

end

System to be solve as an example is

Want δ to vary from 0.3 to 0.5 and

1) plot x1 versus δ

2) x3 versus δ