# Root finding program Newton's Method?

I need help writing a root finding problem using Newton's Method for the following equation:
y = sin(x) − 0.15x + 1.5
I want to use a tolerance of 1.0e-4 and double precision to find all roots (5 total) of the equation.

I would like some assistance on how to go about writing the derivative function to better understand the main program too. Any help is appreciated.

Thanks!
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Commented:
I presume that you mean sin(x) - 0.15x + 1.5 = 0?

But oh my! How Fortran has changed since my day :

http://faculty.washington.edu/rjl/classes/am583s2013/notes/fortran_newton.html

This is a bit more old fashioned (you'll need to change the real*8)

http://jean-pierre.moreau.pagesperso-orange.fr/Fortran/newton1_f90.txt

Incidentally the derivative is cos(x) -0.15.
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