# Malus Law - Cosine squared term?

by Dart82
Tags: cosine, malus, squared, term
 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
 Sci Advisor HW Helper PF Gold 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.
 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 $$sin^{2}x$$ So, to shorten $$(sinx)^2$$ write $$sin^{2}x$$ and to shorten $$sin(x^2)$$ write $$sinx^2$$ (although some people prefer those parenthesis are left in the latter case.)
 P: 58 Malus Law - Cosine squared term? ahhh...thanks for the clarification guys. you've made my day a lot easier!

 Related Discussions Classical Physics 3 Advanced Physics Homework 1 Quantum Physics 1 General Physics 1 Advanced Physics Homework 1