FORTRAN 90

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Q /GA

t find the solution of the following system of equations by

Cramer's rule. Calculate the determinant by subroutine program.

2x1 + x2 + x3 = 3 x1 x2 x3 = 0 x1 + 2x2 + x3 = 0

program cramer_rule

implicit none

integer::i,j,d1,d2,d3 ,det

integer,parameter::n=3

real,dimension(n,2*n-1)::a,a1,a2,a3

real,dimension(n)::b

real::x1,x2,x3

data b/3,0,0/

read(*,*)((a(i,j),j=1,n),i=1,n)

call determinant (a,det)

a1=a;a2=a;a3=a

do i=1,n

a1(i,1)=b(i)

enddo

call determinant (a1,d1)

x1=d1/det

do i=1,n

a2(i,2)=b(i)

enddo

call determinant (a2,d2)

x2=d2/det

do i=1,n

a3(i,3)=b(i)

enddo

call determinant (a3,d3)

x3=d3/det

print*,"x1=",x1 ,"x2=" ,x2 , "x3=",x3 ; end

subroutine determinant (a,det)

implicit none

integer,parameter::n=3

real,dimension(n,2*n-1)::a

integer::i,j ,d1,d2,det

do i=1,n

do j=1,n-1

a(i,n+j)=a(i,j)

enddo ; enddo

do i=1,n; d1=1;d2=1

do j=1,n

d1=d1*a(j,i+j-1)

d2=d2*a(j,2*n-i-j+1)

enddo

det=det+d1-d2 ; enddo

end

Q /GB

t

A= IMPLICIT NONE

/Ed'Z/DE^/KE

/Ed'Z/DE^/KE

INTEGER::i, j, N

DATA

KE-

call dd(n,a,b)

-

write(*,*) -

enddo ; print*,"****************"

enddo ; end

SUBROUTINE dd(n,a,b)

IMPLICIT NONE

/Ed'Z/DE^/KE

/Ed'Z/DE^/KE

INTEGER::i, j, N

DO iE-

DO jE-

B(i,jij-ji

ENDDO ; ENDDO

DO iE-

DO jE-

A(i,j)=B(i,j)

ENDDO ; ENDDO ; END