Chapter 8 - Techniques of Integration - Chapter Review Exercises - Page 460: 62

$$2 \tanh ^{-1}(0.3)=0.619$$

Given $$\int_{-0.3}^{0.3} \frac{d x}{1-x^{2}}$$ Then \begin{aligned} \int_{-0.3}^{0.3} \frac{d x}{1-x^{2}} &=2\int_{0}^{0.3} \frac{d x}{1-x^{2}} \\ &=2\left.\tanh ^{-1} x\right|_{0} ^{0.3} \\ &=2 \tanh ^{-1}(0.3)=0.619 \end{aligned}