If the coordinate velocity v dx/dt in units of c is (e 2 − 1)/(e 2 + 1) ≅ 0.761, what is the velocity angle η in i-radians?
CREATE TABLE "table1_15314901_1" (
  "condition_parameter" text,
  "coordinate_velocity_v_dx_dt_in_units_of_c" text,
  "velocity_angle_in_i_radians" text,
  "proper_velocity_w_dx_d_in_units_of_c" text,
  "lorentz_factor_dt_d_e_mc_2" text
);
SELECT "velocity_angle_in_i_radians" FROM "table1_15314901_1" WHERE "coordinate_velocity_v_dx_dt_in_units_of_c"='(e 2 − 1)/(e 2 + 1) ≅ 0.761';