Does cos + sin always equal 0?

In summary, the conversation discusses whether cos + sin can equal 0 and provides examples of when this may occur or not occur. It is clarified that cos and sin are functions and do not have a specific value. The conversation also mentions that the function f(x) may have x values where it equals 0. The conclusion is that cos + sin does not equal 0 unless certain conditions are met, such as in the equation \cos^2 x + \sin^2 x = 1.
  • #1
Ry122
565
2
does cos + sin = 0?
 
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  • #2
cos + sin can never be equal to anything other than cos + sin. sin and cos are just functions. Neither has a "value" as such.

Do you want to if sin(somevalue1) + cos(somevalue2) = 0?
 
  • #3
Ry122 said:
does cos + sin = 0?

like neutrino said cos + sin have no meaning. But if we get let's say

sin(2n pi)+ cos[(pi/2)+n pi] =0, and there are more samples like this. if this is what you meant at first place?
 
  • #4
did you mean [tex]cosx+sinx=0 [/tex] ?
[tex]\mbox{for the above to be true},\\ cosx=-sinx \\ \Rightarrow cotx=-1 [/tex] (or [tex]sinx=0[/tex] but this does not hold for that.)
 
  • #5
Please only post calculus questions in this forum.
 
  • #6
ChaoticLlama said:
Please only post calculus questions in this forum.
LOL,this may well be calculus...
[tex]Max(sinx+cosx)= \sqrt{2}[/tex]
[tex]Min(sinx+cosx)= -\sqrt{2}[/tex]
Since they function is continuous, it must have x such that f(x)=0
 
  • #7
To OP: Short answer. No.
 
  • #8
Wait up, perhaps you got confused with this:

[tex]\cos^2 x + \sin^2 x = 1[/tex]
 

1. What is the addition formula for sin and cos?

The addition formula for sin and cos is sin(x+y) = sin(x)cos(y) + cos(x)sin(y).

2. How do you simplify the addition of sin and cos?

To simplify the addition of sin and cos, you can use the trigonometric identities to convert the sin and cos terms into one type of trigonometric function, such as sin or cos. Then, you can combine like terms and use the Pythagorean identity to simplify further.

3. Can the addition of sin and cos be applied to any angles?

Yes, the addition formula for sin and cos can be applied to any angles, whether they are in degrees or radians. However, it is important to make sure that the angles are in the same unit before adding them together.

4. Are there any other addition formulas for trigonometric functions?

Yes, there are addition formulas for other trigonometric functions such as tan and cot. For example, the addition formula for tan is tan(x+y) = (tan(x) + tan(y)) / (1 - tan(x)tan(y)).

5. How is the addition formula for sin and cos useful in real-world applications?

The addition formula for sin and cos is commonly used in physics, engineering, and other fields to model and analyze periodic phenomena. It can also be used to solve trigonometric equations and to find solutions to real-world problems involving angles and distances.

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