### Home > CALC > Chapter 5 > Lesson 5.2.5 > Problem 5-105

5-105.

One purpose of tangent lines:

Since evaluating square roots is more challenging than evaluating straight lines, and since the straight line (tangent line) is very close to the square root near its point of tangency, we will evaluate the tangent line at *x* = 0.1 and *x* = −0.1 in order to approximate the values of the square root graph.

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