Table schema:
CREATE TABLE table_15314901_1 (coordinate_velocity_v_dx_dt_in_units_of_c VARCHAR, velocity_angle_η_in_i_radians VARCHAR)

Question: What is the coordinate velocity v dx/dt in units of c total number if the velocity angle η in i-radians is ln[2 + √5] ≅ 1.444?
SQL: SELECT COUNT(coordinate_velocity_v_dx_dt_in_units_of_c) FROM table_15314901_1 WHERE velocity_angle_η_in_i_radians = "ln[2 + √5] ≅ 1.444"