Q. Explain how to find the equation of a tangent line to a curve using differential calculus and explain why such a line is useful?
I know the usual process to find the equation of tangent line. The process is, find a derivative of the function at that point, which will be the slope of the tangent line at that point. Then we use the point-slope formula to point the equation of the tangent.
I am a little bit confused about the use of that tangent line. Could you please explain to me, what is use of this tangent line?