Solving a problem in physics section 39 point 67 optics

Solving a problem in physics section 39 point 67 optics

67. Natural light intensity I0 passes through the polarizer and the analyzer, the angle between the principal plane of which is α. After the passage of light through the system it falls on the mirror and reflected passes through it again. Ignoring the absorption of light to determine the intensity of light I after his return passage.

Additional information:

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)