Angle Between Two Lines Formula?? (1 Viewer)

[esieff]

I can remember that if its the line, and the angle it makes with the axis its just tan@=m But what is the formula for the angle created by two intersecting lines???

 

[Epitome of Lazy]

I'd say tan m (of the greater gradient) - tan m (smaller gradient)...
If i understand what you're trying to say

 

[esieff]

No - I KNOW theres a specific formula, just I can't bloody find it! RAHH!

 

[word.]

that is extension-1 work and it won't be required for the upcoming exam

if m₁ and ₂ are the gradients of the two lines,
then tan@ = |m₁ - m₂|/(1 + m₁m₂)

 

[esieff]

Oh is it? Sweet. Bloody useless 3-unit crap. I don't need you till Thursday. Thanks anyway word. - saved me alot of pointless panic lol.

 

[Riviet]

When doing the absolute value, it's the ab. value of the whole thing.