SIN {{130}^{o}}\COS {{80}^{o}},\] \[y=\sin {{80}^{o}}\cos {{130}^{o}}\] Þ \[x=\cos {{40}^{o}}\cos {{80}^{o}},\,\,\,y=-\sin {{80}^{o}}\sin {{40}^{o}}\] So, \[x>0\] and \[y<0and\]\[XY<0\] Now\[z=1+xy\] Þ \[0