Example Differntiate the following trig function.

$\displaystyle \displaystyle{y = \tan{3x} + \sec{2x}} $

Answer To find the derivative, it is important to know the following rules.

1. The derivative of a sum is the sum of the derivatives. $(f(x) + g(x))' = f'(x) + g'(x)$  
2. The derivative of a constant multiple is the constant times the derivative. $(\alpha f(x))' = \alpha f'(x)$  
3. Basic formula for derivatives. $(\tan{x})' = \sec^{2}{x}, (\sec{x})' = \sec{x}\tan{x}$  

Apply these rules to the above problem, we have

$\displaystyle (\tan{3x} + \sec{2x})'$ $\displaystyle =$ $\displaystyle (\tan{3x}5)' + (\sec{2x})'$  
  $\displaystyle =$ $\displaystyle 3\sec^{2}{3x} + 2\sec{2x}\tan{2x}$