pleasee help!!! Finding the angle of rotation of an ellipse from its general equation

''identify the graph of the equation 2x^2+9xy+14y^2-5=0. then find θ''

Question

pleasee help!!! Finding the angle of rotation of an ellipse from its general equation

''identify the graph of the equation 2x^2+9xy+14y^2-5=0. then find  θ''

anonymous · Answer

@Loser66 do u know how to do this?

anonymous · Answer

@hoblos

accessdenied · Answer

What have you tried with this question so far?

anonymous · Answer

the graph is an ellipse and i have to use this formula to find theta :
Tan2θ=B / A - C 

soo... 
tan2θ= 9 / 2-14
tan2θ= -0,75

accessdenied · Answer

I believe that formula looks correct to what I recall, along with the work..
Alright, so you have: 
   $ \displaystyle \tan 2\theta = - \frac{3}{4} $
You could find the arctangent of each side and then divide by 2.
   $ \displaystyle \theta = \frac{1}{2} \tan^{-1} \left( -\frac{3}{4} \right) $
This could be done on a calculator, or there might be an exact answer using trigonometry.  Shall i go into that?

anonymous · Answer

hmm...how do you do tan^-1 on the calculator

accessdenied · Answer

Do you have a key for tangent?  It is usually 2nd + tangent on mine.

anonymous · Answer

yeah found it! thank you SOOO much!!!! <3

accessdenied · Answer

You're welcome!  :)