typos in comments corrected

SRC/differentiate.f90

@@ -8,7 +8,7 @@ subroutine differentiate(x,y,z,n,f,fx,fy,fz)
 !                   n                 - number of functions to differentiate
 !                   f(4,n)            - values of functions at the vertices
 ! Output parameters:
-!           Formal: fx(n),fy(n),fz(n) - deivatives of functions over x,y and z, resp.
+!           Formal: fx(n),fy(n),fz(n) - derivatives of functions over x,y and z, resp.
 !
 ! Called routines:  dgesv             - from the Lapack library
 !

SRC/tetra_physics_mod.f90

@@ -10,7 +10,7 @@ module tetra_physics_mod
       double precision :: dist_ref               ! normal distance of vertex1 to face1 * |n_1| <-- normal vector to face 1
       double precision, dimension(4)    :: dist_ref_vec
       double precision :: tetra_dist_ref         ! distance reference of a tetrahdron in unit length
-      double precision, dimension(3,4) :: anorm  ! normals to faces pointing invards
+      double precision, dimension(3,4) :: anorm  ! normals to faces pointing inwards
       !Field properties
       double precision, dimension(3)   :: curlA  ! $\epsilon^{ijk}\difp{A_k}{x^j}$ = vector a_4^i ("curl A")
       double precision :: bmod1                  ! module of B in the first vertex