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Math.Cos2 from Math.cos?

Started by socialdev Nov 15, 2011 at 12:48 AM 4 replies 1.3k views

Original Post

Nov 15, 2011 at 12:48 AM

I have a little problem here... The language I am using does not have Math.cos2() function, it only has a Math.cos() function. How do I solve this?

I was looking at the wikipedia article on cosigns and am stumped...
http://en.wikipedia.org/wiki/Law_of_cosines

If it's not included in the language it must be something simple like Math.pow(Math.cos(x),2)? (Cos the the power of two.) Dunno...

alvaro

Nov 15, 2011 at 1:01 AM

I've never heard of cos2. What is it?

TheUnbeliever

Nov 15, 2011 at 1:16 AM

If you mean the thing which appears in $bb23b7b4674a128b573fcd3239d8dd90.png$ then that is indeed just cos(x)^2, which you can get using Math.Pow like you say.

TomKQT

Nov 15, 2011 at 8:24 AM

It's just a little bit confusing way (but fully fine, standard and common) how to write a square of cosinus.
In fact this:
cos[sup]2[/sup]a
simply means:
(cos(a))[sup]2[/sup]

Which really is Math.pow(Math.cos(x),2)

socialdev

Nov 15, 2011 at 11:45 PM

Awesome, thanks Tom.

Cornstalks

Nov 15, 2011 at 11:56 PM

Just to add. One of the reasons we write it like that is so that it's clear we are taking the square of the result of the cos, and not squaring the angle within the cos. Plus I get to be lazy and not write parenthesis.

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