Save guides, add subjects and pick up where you left off with your BBC account. To find the equation of a circle when you know the radius and centre, use the formula \({(x - a)^2} + {(y - b)^2} ...

Find the equation of the tangent to the circle \(x^2 + y^2 = 25 \) at the point (3, -4). The tangent will have an equation in the form \(y = mx + c\) so to find the equation you need to find the ...