Trigonometry sin cos Question

  • Thread starter basty
  • Start date
95
0
I know that ##\sin^2 x + cos^2 x = 1.##

Is this mean that

##\sin^2 2x + \cos^2 2x = 1##

or

##\sin^2 3x + \cos^2 3x = 1##

or

##\sin^2 4x + \cos^2 4x = 1##

and so on?
 
21,992
3,272
Yes.
 
32,744
4,470
I know that ##\sin^2 x + cos^2 x = 1.##

Is this mean that

##\sin^2 2x + \cos^2 2x = 1##

or

##\sin^2 3x + \cos^2 3x = 1##

or

##\sin^2 4x + \cos^2 4x = 1##

and so on?
##sin^2(\text{whatever}) + cos^2(\text{whatever}) = 1##
The "whatever" in both places has to be the same, of course.
 
95
0
Does ##\sin^2 2x = \frac{1 - \cos 4x}{2}?##
 
32,744
4,470
Does ##\sin^2 2x = \frac{1 - \cos 4x}{2}?##
##\sin^2(A) = \frac{1 - \cos(2A)}{2}##
If A = 2x, what is 2A?
 

Related Threads for: Trigonometry sin cos Question

  • Posted
Replies
3
Views
2K
  • Posted
Replies
4
Views
2K
  • Posted
Replies
4
Views
2K
  • Posted
Replies
13
Views
758
  • Posted
Replies
16
Views
9K
  • Posted
Replies
1
Views
1K
Replies
5
Views
543
  • Posted
Replies
2
Views
609

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top