Starting at the origin, draw a line segment 2 units along the positive x-axis. Draw a second line segment from that point 1 unit in the positive y direction. You are now at point (2, 1), so label this point P. Draw a line between O and P. This line has length r{\displaystyle r} in polar coordinates. It is also the hypotenuse of a right triangle, so you can find the hypotenuse's length using geometry. For example:  The legs of this right triangle have values of 2 and 1. With the Pythagorean theorem, calculate that the hypotenuse's length is 22+12=4+1=5≈2.236{\displaystyle {\sqrt {2^{2}+1^{2}}}={\sqrt {4+1}}={\sqrt {5}}\approx 2.236}. The general formula to find r{\displaystyle r} from Cartesian coordinates is r=x2+y2{\displaystyle r={\sqrt {x^{2}+y^{2}}}}, where x{\displaystyle x} is the Cartesian x-coordinate and y{\displaystyle y} the Cartesian y-coordinate. Use trigonometry to find this value:   tan⁡(θ)=oppositeadjacent=12{\displaystyle \tan(\theta )={\frac {opposite}{adjacent}}={\frac {1}{2}}}tan−1⁡(12)=θ=26.56∘{\displaystyle \tan ^{-1}({\frac {1}{2}})=\theta =26.56^{\circ }}  The general formula to find θ{\displaystyle \theta } is θ=tan−1⁡(yx){\displaystyle \theta =\tan ^{-1}({\frac {y}{x}})}, where y{\displaystyle y} is the Cartesian y-coordinate and x{\displaystyle x} the Cartesian x-coordinate. You now have the values of r{\displaystyle r} and θ{\displaystyle \theta }. The rectangular coordinates (2, 1) convert to approximate polar coordinates of (2.24, 26.6º), or exact coordinates of (5,tan−1⁡(12)){\displaystyle ({\sqrt {5}},\tan ^{-1}({\frac {1}{2}}))}.

Summary: Consider the point P(2,1){\displaystyle P(2,1)} in the Cartesian plane. Find the distance between the origin O{\displaystyle O} and P{\displaystyle P}. Find the angle between OP{\displaystyle OP} and the positive x-axis. Write down the polar coordinates.


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Summary: Ensure you know and trust the sender before opening an email. Check the subject line for common spam topics. Avoid any "calls to action" or requests for personal information. Hover over any links in the email to see if they match their supposed destination. Look for typos, especially of key phrases or words. Never open or download attachments unless you know what they are. Type in any links directly instead of clicking on the links. Use 3rd-party security sites to test emails and links you're still worried about. See if the message was diverted to the spam folder.