11-19-2017, 03:39 PM (This post was last modified: 11-19-2017 03:39 PM by DrD.)
Post: #1
 DrD Senior Member Posts: 1,132 Joined: Feb 2014
If there is a lexicon formality, how should equal power terms involving cos() and sin() be displayed in "proper" order?

Here's an example:

y:=cos(x^4)^2;
y'; ==> -2*4*x^3*sin(x^4)*cos(x^4) Notice the factoring order
collect(y'); ==> -8*x^3*cos(x^4)*sin(x^4) The cos() and sin() get reversed here.

(In this case increasing power order): Without any mathematical difference, what, if any, is the proper, or most formal way to express the ordering of the trig terms?
11-19-2017, 03:58 PM (This post was last modified: 11-19-2017 04:00 PM by salvomic.)
Post: #2 salvomic Senior Member Posts: 1,392 Joined: Jan 2015
RE: Trivia: Question about arranging terms
(In this case increasing power order): Without any mathematical difference, what, if any, is the proper, or most formal way to express the ordering of the trig terms?
[/quote]

In the old Italian books of trigonometry we have: SIN, COS, TAN and decreasing power order (x^4, x^3, x^2..., about my math professor), but if (generally) COS in x and SIN is y, we should have COS, SIN, TAN, I think...

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