How to Prove tan(a - b) = tana - tanb without using a prefix?

This will give you the desired result of tan(a-b) = tana - tanb / 1 + tanatanb.In summary, to prove that tan(a-b) = tana - tanb / 1 + tanatanb, divide the numerator and denominator by cosacosb. This will result in the desired equation: tan(a-b) = tana - tanb / 1 + tanatanb.
  • #1
Quinn Morris
14
0

Homework Statement



Prove that: tan (a - b) = tana - tanb
1 + tanatanb
]​

Homework Equations



cos (a- b) = cosacosb + sinasinb


sin (a - b) = sinacosb - cosasinb


The Attempt at a Solution



I have plugged in the two equations give above since tan - sin/cos and then I'm am stumped of how to proceed

tan (a - b) = sinacosb - cosasinb
cosacosb + sinasinb

can anyone help please?
 
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  • #2
Quinn Morris said:
tan (a - b) = sinacosb - cosasinb
cosacosb + sinasinb

The formula you are trying to arrive at provides the clue: what could you divide numerator and denominator by to get that "1" in the denominator?
 
  • #3
so times buy a form of one... 1 over cosacosb?
 
  • #4
yes that is correct, divide the numerator and denominator by cosacosb
 

Related to How to Prove tan(a - b) = tana - tanb without using a prefix?

1. What are the "Tough Twelve Trig Formulas"?

The "Tough Twelve Trig Formulas" refer to a set of twelve trigonometric formulas that are commonly used in advanced mathematics and physics. These formulas involve the six trigonometric functions (sine, cosine, tangent, cosecant, secant, and cotangent) and their inverses.

2. Why are these formulas considered tough?

These formulas are considered tough because they are complex and require a deep understanding of trigonometry and mathematical concepts to be applied effectively. They are often used in advanced calculations and can be challenging to memorize and manipulate.

3. What are some practical applications of the "Tough Twelve Trig Formulas"?

The "Tough Twelve Trig Formulas" are used in a variety of fields, including engineering, physics, and astronomy. They are used to calculate the relationships between angles and sides in triangles, which is useful in measuring distances, constructing buildings, and designing machines.

4. How can I remember all of the "Tough Twelve Trig Formulas"?

One way to remember these formulas is by practicing and applying them in different scenarios. You can also create flashcards or mnemonic devices to help you memorize them. Additionally, understanding the underlying concepts and relationships between the formulas can make them easier to remember and apply.

5. Are there any shortcuts or tricks for using the "Tough Twelve Trig Formulas"?

Yes, there are some shortcuts and tricks that can make using these formulas easier. For example, the Pythagorean identities can be used to simplify some of the formulas. Additionally, knowing the unit circle and common angles can help you quickly identify the values of trigonometric functions in certain scenarios.

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