CREATE TABLE table_15314901_1 (proper_velocity_w_dx_dτ_in_units_of_c VARCHAR(255), condition_parameter VARCHAR(255))
If the condition/parameter is rapidity of 1 hyperbolic radian, what is the proper velocity w dx/dτ in units of c?
    
SQL: SELECT proper_velocity_w_dx_dτ_in_units_of_c FROM table_15314901_1 WHERE condition_parameter = "Rapidity of 1 hyperbolic radian"