Trigonometry
r2=16sinθ−39r^2=16\sin\theta-39r2=16sinθ−39
r2=−16rsinθ−39r^2=-16r\sin\theta-39r2=−16rsinθ−39
r2=16rsinθ−39r^2=16r\sin\theta-39r2=16rsinθ−39
r2=16rsinθ+39r^2=16r\sin\theta+39r2=16rsinθ+39