To find the tangent find the derivative of at which isOriginally Posted byfrozenflames

Thus, the slope of the tangent line is . Now use the formula for finding equations of line by knowing thier slopes and the point that they pass through. That formula is this tangent line has slope and passes through the point of tangentcy thus Thus, the equation of the tangent line is thus, now set because this is the x-intercept thus solve for thus

Q.E.D.