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Malus Law  Cosine squared term? 
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#1
Mar607, 03:02 PM

P: 58

this is just a general trig question:
We are going over Malus law in physics; the formula is this: S = s*cos^2(theta) My question is about the cosine squared term in the equation. does this simply mean take the cosine of a number and square it? in other words would this be the same thing as [cos(theta)]^2 


#2
Mar607, 03:04 PM

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P: 12,016

Indeed!
It is an unfortunate notation that confuses a lot of students, but it won't ever go away. you have to live with it. 


#3
Mar607, 03:18 PM

P: 291

I simply tell my students that once upon a time, they wrote it as (sinx)^2, but lazy students kept leaving off the parenthesis and wrote sinx^2, sometimes meaning to take the sine of x, then square that answer; other times meaning to square the x first, then take the sine. To eliminate confusion, when they want the sin value to be squared, they put the squared symbol right next to sin
[tex]sin^{2}x[/tex] So, to shorten [tex](sinx)^2[/tex] write [tex]sin^{2}x[/tex] and to shorten [tex]sin(x^2)[/tex] write [tex]sinx^2[/tex] (although some people prefer those parenthesis are left in the latter case.) 


#4
Mar607, 05:44 PM

P: 58

Malus Law  Cosine squared term?
ahhh...thanks for the clarification guys. you've made my day a lot easier!



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