Math Is Fun Forum

mathland

Member

Registered: 2021-03-25

Posts: 444

Law of Tangents

I know there is a law of sines and law of cosine in trigonometry.
What about the law of tangents? Why is the law of tangents ever used in trigonometry textbooks?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Law of Tangents

Are you talking about the sine rule and the cosine rule?

This link shows  what the first is. 

https://www.mathsisfun.com/algebra/trig-sine-law.html

If that's what you mean (I know you are familiar with it, just trying to make sure we're talking about the same thing) then I'll attempt to answer your original question.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: Law of Tangents

Are you talking about the sine rule and the cosine rule?

This link shows  what the first is. 

https://www.mathsisfun.com/algebra/trig-sine-law.html

If that's what you mean (I know you are familiar with it, just trying to make sure we're talking about the same thing) then I'll attempt to answer your original question.

Bob

Hi Bob. How are you? I am specifically talking about the law of tangents. I think there is a law of tangents. In fact, I know there is a law of tangents.

1. When do we use the law of tangents?

2. Why isn't this law discussed in trigonometry textbooks?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Law of Tangents

Look it up on Wikipedia.

B

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: Law of Tangents

Look it up on Wikipedia.

B

Online sources use math jargon to explain this law. No problem. I will also look it up on You Tube.