finding tangent on a scientific calculator

Question

I am finding the resultant force of two vectors. I understand everything except the last step. I have come to the following step:

 

tan θ = -22.28/12.26

 

To show you the process, I will show you an example I am given:

 

tan θ = 12.56/-2.60

 

θ = 101.70°

 

How do I solve my equation?

 

 

Answer 1

What you solved was the direction of the vector.  To find the resultant, use the x and y components of the vectors and apply the pythagoraean theorem.

 

If tanθ = y / x

 

and

 

x = -2.60

y = 12.56

 

then

 

(-2.60)² + (12.56)² = R²

 

164.51 = R²

 

12.83 = R

 

 

The magnitude of the second vector is 12.83 

 

Answer 2

Use Tan^-1 function to find Θ