recurrence relations

I need to solve the following recurrence relation:

n-cube not planar for n>4

I need to prove the n-cube Qn is not planar for n greator than or equal to 4

planar graph vertex degree at most 5

I need to show that if G is a planar graph, then G must have a vertex of degree at most 5.

Discrete Math

Discrete Math True or False questions

EQUIVALENCE RELATIONS

Verify that each of the following are equivalence relations on the plane R^2 (where R are real numbers) and describe the equivalence classes geometrically. 1) (x1,y1)R(x2,y2) if and only if x1 = x2 2) (x1,y1)R(x2,y2) if and only if x1 + y1 = x2+y2 3) (x1,y1)R(x2,y2) if and only if x1^2 + y1^2 = x2^2 + y2^2