Unpolarized light is incident on a system of three polarizers. The second polarizer is oriented at an angle of 28.0° with respect to the first and the third is oriented at an angle of 45.0° with respect to the first. If the light that emerges from the system has an intensity of 2.1 W/m2, what is the intensity of the incident light?
is this what you do: 2.1W/m^2 divided by cos^2(21). then divide that answer by cos^2(28) than multiply that anwswer by 2? I can's eem to get the right anwser to cos2(21) and cos2(28) right in my calculator. I need some help