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If theta\ is the angle which the straig...

If `theta\ ` is the angle which the straight line joining the points `(x_1, y_1)a n d\ (x_2, y_2)` subtends at the origin, prove that `tantheta=(x_2y_1-x_1y_2)/(x_1x_2+y_1y_2)\ a n dcostheta=(x_1x_2+y_1y_2)/(sqrt(x1 2 x2 2+y2 2x1 2+y1 2x2 2+ y1 2y2 2))`

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RD SHARMA ENGLISH-THE STRAIGHT LINES -All Questions
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  16. Find the perpendicular distance of the line joining the points (costhe...

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