The angle that A makes with the positive x axis

[Deading]

A=2i-10k

give the angle that A makes with the positive x-axis ?


do i need to make x axis=i and i go A.B/AxB ?

 

[Spinnor]

You have short sides of a triangle, you want the inverse tangent, see:

http://math12.vln.dreamhosters.com/wiki/Modeling_Real_World_Situations_Using_Trigonometric_Functions#Tangent_of_Theta

 

[tebes]

Is this 3-dimesional question?

 

[NascentOxygen]

Is this 3-dimesional question?

It is. But don't be put off, because it's actually an easy 3D question.

 

[rwisz]

I would first clarify that A is a vector with components of 2i and -10k. Then, I would explain that to find the angle that A makes with the positive x-axis, we can use the dot product formula A·B = |A||B|cosθ, where A and B are two vectors and θ is the angle between them. In this case, we can take B to be the unit vector in the positive x-axis direction, which is simply i. So, A·i = |A||i|cosθ = 2cosθ. We can solve for θ by taking the inverse cosine of 2cosθ, which gives us the angle between A and the positive x-axis.