# Math Help - angel of intersection between curves in 3D

1. ## angel of intersection between curves in 3D

Ok, the question's like this...

The curves r1(t)=<t,t^2,t^3> and r2(t)=<sin t, sin 2t, t> intersect at the origin. Find their angle of intersection correct to the nearest degree.

Thank you so much!

2. Originally Posted by violet8804
Ok, the question's like this...

The curves r1(t)=<t,t^2,t^3> and r2(t)=<sin t, sin 2t, t> intersect at the origin. Find their angle of intersection correct to the nearest degree.

Then use $tan(\theta- \phi)= \frac{tan(\theta)- tan(\phi)}{1+ tan(\theta)tan(\phi)}$.