Question 624315
Write an equation of the line tangent to the given circle at the given point. I have an idea on how to do it but I often mess up.  
x^2+y^2=13  (2,3)
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Equation of a straight line: y=mx+b, m=slope, b=y-intercept
slope of tangent line=negative reciprocal of slope of line from given point(2,3) to center of circle (0,0)
slope=∆y/∆x=(3-0)/(2-0)=3/2
negative reciprocal=-2/3
Equation of tangent line: y=-2x/3+b
solve for b using coordinates of given point (2,3)
3=-2*2/3+b
b=3+4/3=13/3
equation of line tangent to circle: y=-2x/3+13/3
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