# Two Different Angle Vector Formulas ?

#### Jason76

Formula to find the angle between vectors:

$$\displaystyle |a|\,\,|b| = \cos\theta$$

or

$$\displaystyle \cos\theta = \dfrac{a\,\,*\,\,b}{|a|\,\,|b|}$$

where a and b are vectors

When should we use one formula rather than the other?

#### Plato

MHF Helper
Formula to find the angle between vectors:

$$\displaystyle {a\cdot b} ={|a|\,\,|b|} \cos\theta$$

or

$$\displaystyle \cos\theta = \dfrac{a\,\,*\,\,b}{|a|\,\,|b|}$$

where a and b are vectors

When should we use one formula rather than the other?
Well if you know middleschool basic algebra, then you realize they are identical.

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