Sunday

April 20, 2014

April 20, 2014

Posted by **bill** on Monday, March 22, 2010 at 10:08am.

- trig -
**Reiny**, Monday, March 22, 2010 at 10:59amIt is a very simple concept to learn

Polar coordinates have the form (r,Ø)

where r is the length of a rotating arm, usually r is positive, and Ø is the angle it points to.

So draw a standard x-y intersecting axes

the normal point (0,)) is the centre of rotation, with the positive x-axis as the 0 direction.

Rotation is counterclockwise.

so a polar point of (4,π/6) would be a rotating arm of length 4 rotated through π/6 radians or 30 degrees.

Unlike rectangular coordinates, polar coordinate points are not uniquely defined.

e.g. (5, π/3) ends up in the same place as (5,-5π/3) or (5,7π/3).

My angles are all coterminal, that is they end up in the same direction.

to convert from one to the other, ....

1. polar to rectangular:

x = rcosØ

y = rsinØ

2. rectangular to polar

r = √(x^2 + y^2) , which is just using Pythagoras

Ø = arctan(y/x)

**Related Questions**

Pre-Calc - Can anyone direct me to learn more about polar coordinates. I'm in ...

pre-calculus - Graph the polar equation: 2=r cos(theta + 180) 2=r(costheta ...

Calculus please help ! - 1.Graph the polar equation r=3-2sin(theta) 2. Find the ...

Math ! Please Help ! - 1.Graph the polar equation r=3-2sin(theta) 2. Find the ...

Pre-calculus; urgent ! Please help ! - 1.Graph the polar equation r=3-2sin(theta...

trig - Given the polar coordinates of a point, how do I find the rectangular ...

trig - How do you convert polar coordinates to Cartesian coordinates? And vise ...

trig - convert the point with polar coordinates (2,7pi/6) into rectangular ...

Math (Calculus) - Given any Cartesian coordinates, (x,y), there are polar ...

Math Graph - In polar coordinates, the graph r=sin(θ)/cos^2(θ) ...