Proving tan(45+x)=cot(45-x) in Degrees

  • Thread starter Miike012
  • Start date
  • Tags
    Trig
In summary, proving an equation involving trigonometric functions means demonstrating that it holds true for all possible values of the variables involved. To do this, we often use identities and properties of trigonometric functions, such as the sum and difference identities for tangent and cotangent. Specifically, to prove the equation tan(45+x)=cot(45-x) in degrees, we can use the sum identity for tangent to rewrite tan(45+x) as (tan45 + tanx) / (1 - tan45 tanx) and the difference identity for cotangent to rewrite cot(45-x) as (cot45 cotx + 1) / (cot45 - cotx). However, we must keep in mind restrictions and special cases
  • #1
Miike012
1,009
0

Homework Statement


Prove: tan( 45 + x) =cot( 45 - x )

Note: the numbers that I am using are in deg.

Working with left side:
tan( 90 - 90 + 45 + x )
=tan(90 - 45 + x)
=tan(90 -(45+x))
=cot(45 +x)
Is my algebra correct?

If so why am I getting pos x and not a neg x?
and if this is true that is kind of weird that tan (90+x) = cot(90+x)



Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
  • #2
Nevermind... I did not factor out a neg 1 from the x.. I know what I did wrong ..
 

Related to Proving tan(45+x)=cot(45-x) in Degrees

1. What does it mean to "prove" an equation involving trigonometric functions?

To prove an equation means to show that it is true for all possible values of the variables involved. In this case, we need to show that the equation tan(45+x)=cot(45-x) is true for all values of x measured in degrees.

2. How do you approach proving a trigonometric equation?

To prove a trigonometric equation, we often use identities and properties of trigonometric functions. In this case, we can use the sum and difference identities for tangent and cotangent to rewrite the equation into a more easily recognizable form.

3. What are the sum and difference identities for tangent and cotangent?

The sum identity for tangent states that tan(A+B) = (tanA + tanB) / (1 - tanA tanB), while the difference identity for cotangent states that cot(A-B) = (cotA cotB + 1) / (cotA - cotB). These identities will be useful in proving the given equation.

4. Can you briefly explain the steps to prove tan(45+x)=cot(45-x) in degrees?

Sure! First, we will use the sum identity for tangent to rewrite tan(45+x) as (tan45 + tanx) / (1 - tan45 tanx). Next, we will use the difference identity for cotangent to rewrite cot(45-x) as (cot45 cotx + 1) / (cot45 - cotx). Then, we can simplify both sides of the equation and show that they are equal, which proves the given equation.

5. Are there any special cases or restrictions to consider when proving this equation?

Yes, we need to make sure that the angles involved are measured in degrees, since the given equation is in degrees. We also need to be careful when dividing by trigonometric functions, as they can sometimes equal zero or be undefined.

Similar threads

  • Precalculus Mathematics Homework Help
Replies
15
Views
2K
  • Precalculus Mathematics Homework Help
Replies
5
Views
2K
  • Precalculus Mathematics Homework Help
Replies
3
Views
2K
  • Precalculus Mathematics Homework Help
Replies
7
Views
2K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
  • Precalculus Mathematics Homework Help
Replies
15
Views
2K
  • Precalculus Mathematics Homework Help
Replies
10
Views
2K
  • Precalculus Mathematics Homework Help
Replies
22
Views
4K
  • Precalculus Mathematics Homework Help
Replies
15
Views
3K
Back
Top