# Principal Normal Section [closed]

On the surface $$x=u^2+v^2, \ \ \ y=u^2-v^2,\ \ \ z=uv$$ we take the point $P(u=1,v=1)$.

$1)$ Compute the principal curvatures of the surface at point $P.$

$2)$ Find the equations of the tangents $PT_1, \ PT_2$ to the principal normal sections at the indicated point.

$3)$ Find the curvature of the normal section passing through the tangent to the curve $v=u^2$

I have solved the first point and the principal curvatures are: $$\kappa_1=0, \ \kappa_2=\frac{160}{80^{\frac{3}{2}}}$$

but I do not know what should I do in the next two points. So, can someone please help me ?

## closed as off-topic by user99914, Claude Leibovici, Juniven, Jaideep Khare, zz20sMay 15 '17 at 11:49

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Community, Claude Leibovici, Juniven, Jaideep Khare, zz20s
If this question can be reworded to fit the rules in the help center, please edit the question.

• Can anyone help me please ? – Hitman May 15 '17 at 9:42