<Dl> <Dd> tan 2 ⁡ θ = 1 − cos 2 ⁡ θ cos 2 ⁡ θ = v 2 2 g y 0 + v 2 = 1 C + 1 (\ displaystyle \ tan ^ (2) \ theta = (\ frac (1 - \ cos ^ (2) \ theta) (\ cos ^ (2) \ theta)) = (\ frac (v ^ (2)) (2gy_ (0) + v ^ (2))) = (\ frac (1) (C + 1))) </Dd> </Dl> <Dd> tan 2 ⁡ θ = 1 − cos 2 ⁡ θ cos 2 ⁡ θ = v 2 2 g y 0 + v 2 = 1 C + 1 (\ displaystyle \ tan ^ (2) \ theta = (\ frac (1 - \ cos ^ (2) \ theta) (\ cos ^ (2) \ theta)) = (\ frac (v ^ (2)) (2gy_ (0) + v ^ (2))) = (\ frac (1) (C + 1))) </Dd> <P> Multiplying with the equation for (tan ψ) ^ 2 gives: </P> <Dl> <Dd> tan 2 ⁡ ψ tan 2 ⁡ θ = 2 g y 0 + v 2 v 2 v 2 2 g y 0 + v 2 = 1 (\ displaystyle \ tan ^ (2) \ psi \, \ tan ^ (2) \ theta = (\ frac (2gy_ (0) + v ^ (2)) (v ^ (2))) (\ frac (v ^ (2)) (2gy_ (0) + v ^ (2))) = 1) </Dd> </Dl>

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