Boyan

Hello. I have problems with this problem. I find that the coordinates of A are (-4;3) but what I am supposed to do after that?

http://img21.imageshack.us/img21/814...roblemq.th.jpg

Help me please

An0maly

Take the center of the circle, which is (0,0), and label it O. Then, OA is a radius. Since line L is tangent, it means it is perpendicular to the radius. The slope of perpendicular lines are opposite reciprocals. So:

slope of OA = (3 - 0)/(-4 - 0) = -3/4

Opposite reciprocal: 4/3. So, the slope of line L is 4/3.

Alternatively, if you know calculus, just do implicit differentiation for a fast solution.

Ashika

Wanna get a higher resolution picture btw..

Boyan

Thanks for the solution. Sorry for the resolution - I thought it was bigger.