• Support PF! Buy your school textbooks, materials and every day products Here!

Malus Law - Cosine squared term?

  • Thread starter Dart82
  • Start date
  • #1
57
0
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
 

Answers and Replies

  • #2
arildno
Science Advisor
Homework Helper
Gold Member
Dearly Missed
9,970
131
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
286
0
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.)
 
Last edited:
  • #4
57
0
ahhh...thanks for the clarification guys. you've made my day a lot easier!
 

Related Threads on Malus Law - Cosine squared term?

  • Last Post
Replies
4
Views
903
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
6
Views
4K
  • Last Post
Replies
4
Views
8K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
8
Views
12K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
4
Views
3K
  • Last Post
Replies
7
Views
6K
Top