Geo5.4.1

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What are the polar coordinates of (-1,-1)\,

Let (r,\theta )\, be the polar coordiantes of (1,-1).

x=r\cos \theta =-1,y=r\sin \theta =-1,x^{2}+y^{2}=r^{2}\,

r={\sqrt  {2}}\,

\cos \theta =-{\frac  {1}{{\sqrt  {2}}}},\sin \theta =-{\frac  {1}{{\sqrt  {2}}}}\,

Hence \theta ={\frac  {5\pi }{4}}\,

Therefore the polar coordinates are ({\sqrt  {2}},{\frac  {5\pi }{4}})\,


Main Page:Geometry:Polar Coordinates