Hi,

I need to rotate a point P1(x1,y1) about a pivot point P2(x2,y2) at an angle 'a'. What is the formula for calulating the new point?

Manu

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- Aug 19th 2009, 12:26 AMManuLiFormula For Rotating a Point about another Point
Hi,

I need to rotate a point P1(x1,y1) about a pivot point P2(x2,y2) at an angle 'a'. What is the formula for calulating the new point?

Manu - Aug 19th 2009, 09:16 AMrunning-gag
- Aug 19th 2009, 04:44 PMHallsofIvy
What running-gag did was "translate" the point $\displaystyle (x_2, y_2)$ to the origin (0,0) (that's the $\displaystyle x_1- x_2$ and $\displaystyle y_1-y_2$ part) then rotate about the origin, the translate back (that's why he added $\displaystyle x_2$ and $\displaystyle y_2$).

- Aug 20th 2009, 09:15 AMrunning-gag