For a given initial projectile speed, you observe that the projectile has a certain range R at a launch angle of 30°. For what other launch angle will the projectile have the same range (assuming the same initial projectile speed)? Show your calculations to prove this. Without the use of a mathematical formula, give a conceptual argument as to why this angle gives the same range (think about the trade-offs between time-of-flight and the horizontal component of velocity in your answer).