Hi i am having trouble with three questions in my calculus assignment, all help is greatly appreciated

Find the equation of the tangent to y= x+lnx which is perpendicular to the line x+2y+3=0. I am not really sure where to start with this one :X

A piece of wire one meter long is to be cut into two pieces one will be used to form a square the other a circle, find the dimensions of the two that will form the least total area.

I'm not sure if this is correct but i subed x=25-.5piR into x^2+piR^2, which gave me (25-.5piR)^2 + piR^2

Determine the stationary points of the curve y=(x^2-1)e^-x. Using the product rule i come up with y'= -(x^2 -1)e^-x+2xe^-x , i am unsure whether i am right up to this point or if it can be simplified any further.

Thanks,

Webby