seeing that r^2(1+m^2)=b^2...use this method to find an equation of the tangent line to the circle x^2+y^2=9 at the point ( 1, 2square root of 2 )
i'm totally lost...thanks in advance
In the given problem r = 3.
Differentiating the equation of the circle, you get m. Thus
2x + 2y*y'= 0 Put the values of x and y and find y' = m.
Using the formula
r^2(1+m^2) = b^2, find b.
Then the equation of the tangent is
y = mx + b.