Find an equation of the tangent line to the parabola y=x2\displaystyle {y}={x}^{{2}} at the point P(2.1,4.41)\displaystyle {P}{\left({2.1},{4.41}\right)}.

Start by calculating the slope of the secant line PQ\displaystyle {P}{Q} for different points Q\displaystyle {Q} that get closer to the point P(2.1,4.41)\displaystyle {P}{\left({2.1},{4.41}\right)}. Fill in this table similar to those in this example by calculating the slope of the tangent lines through P\displaystyle {P} and the point Q(x,x2)\displaystyle {Q}{\left({x},{x}^{{2}}\right)} for the values of x\displaystyle {x} provided in the table.
x\displaystyle {x}^{{\text{}}}mPQ\displaystyle {m}_{{{P}{Q}}}
3
2.5
2.2
2.11
2.101
2.1001
Based on the values in this table, it appears the slope of the tangent line should be m=\displaystyle {m}=

Now that you have the slope m\displaystyle {m} of the tangent line and a point P(2.1,4.41)\displaystyle {P}{\left({2.1},{4.41}\right)} on the tangent line, you can find the equation of the line:
tangent line is y=\displaystyle {y}=