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The source code of Newton–Raphson method.Here the equation x3 - 2x - 5 = 0 is solved by the method of Newton–Raphson in FORTRAN language with CODE::BLOCKS.
The equation x3 - 2x - 5 = 0 is solved here by the method of Newton–Raphson in FORTRAN language with CODE::BLOCKS. We know the method of Newton–Raphson is near to the false position method. Here the trick of algorithm is bellow:
1. Take a point near the solution.
2. Subtract the quotient of the functional value and the derivative functional value of that function in the point.
3. It will be the new point near the solution.
4. When the functional value is equal to zero it will be the exact solution.
The programming source code is given bellow:
program newton
implicit none
real::f,x,fp,x0,x1,tol
integer::itrtn,i
print*,"Enter the initial point:"
read(*,*)x0
print*,"Enter the total iteration:"
read(*,*)itrtn
print*,"Enter the tolerance:"
read(*,*)tol
do 10 i = 1,itrtn
x1 = x0 - f(x0)/fp(x0)
if(f(x1).eq.0) then
print*, "The soln is:",x1
stop
end if
if(abs(x0-x1).le.tol) then
print*,"Approximate soln is:",x1
stop
end if
x0 = x1
10 continue
print*,"Maximum iteration failed"
end program
real function f(x)
real::x
f = x**3 - 2*x - 5
return
end function
real function fp(x)
real::x
fp = 3*x**2 - 2
return
end function