Integral of $$$\frac{1}{\sec{\left(x \right)}}$$$

Find $$$\int \frac{1}{\sec{\left(x \right)}}\, dx$$$.

Rewrite the integrand in terms of the cosine:

$${\color{red}{\int{\frac{1}{\sec{\left(x \right)}} d x}}} = {\color{red}{\int{\cos{\left(x \right)} d x}}}$$

The integral of the cosine is $$$\int{\cos{\left(x \right)} d x} = \sin{\left(x \right)}$$$:

$${\color{red}{\int{\cos{\left(x \right)} d x}}} = {\color{red}{\sin{\left(x \right)}}}$$

Therefore,

$$\int{\frac{1}{\sec{\left(x \right)}} d x} = \sin{\left(x \right)}$$

Add the constant of integration:

$$\int{\frac{1}{\sec{\left(x \right)}} d x} = \sin{\left(x \right)}+C$$

$$$\int \frac{1}{\sec{\left(x \right)}}\, dx = \sin{\left(x \right)} + C$$$A