Question

The nearest star to Earth is Proxima Centauri, 4.2 light-yearsaway.
2 parts..
1st ) At what constant velocity must a spacecraft travel from Earthif it is to reach the star in 3.7 years, as measured by travelerson the spacecraft?

2nd ) How long does the trip take according to Earthobservers?

please show steps with values for each..
like for part 1 I understand the formula to be
L=L₀ [1-(v/c)^2]^.5
and Because the star is moving toward the spacecraft, to cover thisdistance in 4.2 yr, the speed of the
star must be

v=L/t =(4.2/3.7)[1-(v/c)^2]^.5 = 1.135[1-(v/c)^2]^.5

what am i plugging in? or how do i arrange to solve for v..

then I need help with part too as well..

thanks..