Question 839280
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Hi,
equation of tangent to the circle x^2+y^2=a^2 for all values of m at point (x1,y1)
x^2+y^2=a^2   |Differentiating
{{{2x + 2y(dy/dx) = 0}}}
 {{{dy/dx = highlight( -x/y)}}}  |Slope of tangent Line
Tangent Line at point (x1,y1):
{{{y - y[1] = (-x[1]/y[1])(x - x[1])}}}