The trigonometric inverse cosine is **numpy.arccos()** method in Python Numpy.
(See the
numpy.arccos documentation.)

(Also see
numpy.rad2deg documentation.)

(Also see
numpy.deg2rad documentation.)

sin(α) sin(β) sin(δ) -------- = -------- = -------- A B C

Use the Law of Sines to solve oblique triangles. Any triangle that is not a right triangle is an oblique triangle.

*Note: There are three possible oblique triangle problem situations:
ASA (angle-side-angle), AAS (angle-angle-side), and SSA (side-side-angle).*

rise ym = slope (x_{2}- y_{1}m = ---- = ------- run x_{2}- x_{1}_{1},y_{1}) = coordinates of first point in the line (x_{2},y_{2}) = coordinates of second point in the line

The slope of a line parallel to the Y axis is undefined
(x_{2}-x_{1} = 0).

The slope of a line parallel to the X axis is 0
because (y_{2}-y_{1} = 0).

test_arcsin.py

test_arcos.py

calculate the angle between two vectors (line segments)

rotate a line anchored at the origin (0,0)

line_intersection.py

test_line_intersection.py

parallel_lines.py

two_vector_angle.py

test_two_vector_angle.py

test_fold_01.py

test_fold_02.py

These are files you will need for the code examples. They can be found in other project descriptions. Especially the project "Demonstrate using a graphics transformation matrix (2D and/or 3D)".

graphics.py

coordinate_conversion.py

draw_xy_axes.py

transformation_matrix.py

user_interface.py

coordinate_conversion.py

draw_xy_axes.py

transformation_matrix.py

user_interface.py