1.I.3G

Geometry
Part IB, 2004

Using the Riemannian metric

ds2=dx2+dy2y2d s^{2}=\frac{d x^{2}+d y^{2}}{y^{2}}

define the length of a curve and the area of a region in the upper half-plane H={x+iy:y>0}H=\{x+i y: y>0\}.

Find the hyperbolic area of the region {(x,y)H:0<x<1,y>1}\{(x, y) \in H: 0<x<1, y>1\}.