94. $\int \frac{3 d x}{\cos ^{2} x}$.

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94. $\int \frac{3 d x}{\cos ^{2} x}$.
Solution. Directly by formula VII we find

$$
\int \frac{3 d x}{\cos ^{2} x}=3 \int \frac{d x}{\cos ^{2} x}=3 \operatorname{tg} x+C
$$