Adding Vectors: Using Angles and Formulas | Vector Addition Explained

[physics kiddy]

To add two vectors, a$\rightarrow$ and b$\rightarrow$ we use the formula $\sqrt{}$a²+b²+2abcosθ

where θ is the smallest angle between vectors a and b. Is there any way I can use the bigger angle to calculate the sum ? It's not a homework, just a question from my intution.

I have attached a pic also... Thanks in advance for help

 

[tiny-tim]

hi physics kiddy!

Is there any way I can use the bigger angle to calculate the sum ?

you mean 360° - θ ?

but cos(360° - θ) equals cosθ ​

btw, the formula is easier to understand if you draw a and b head-to-tail (instead of tail-to-tail)

 

[Infinitum]

To add two vectors, a$\rightarrow$ and b$\rightarrow$ we use the formula $\sqrt{}$a²+b²+2abcosθ

where θ is the smallest angle between vectors a and b. Is there any way I can use the bigger angle to calculate the sum ? It's not a homework, just a question from my intution.

I have attached a pic also... Thanks in advance for help

To use the bigger angle, all you need to do is to express cos(360-x) in terms of cos(x), which in fact is cos(360-x) = cos(x)