A $60$ deg graphite$/$epoxy lamina is under the stress state sx $=2$MPa, sy $=-3$MPa and txy$=4$MPa. Find the ratio of principal strains g$12/$e$2.$ Use E$1=181$Gpa, E$2=10\mathrm{.}3$ GPa, G$12=7\mathrm{.}17$ GPa and v$12=0\mathrm{.}28$