Find the Curvature of the Curve R(t) $$\mathbf { r } ( \mathrm { t } ) = ( 3 + \ln ( \sec t ) ) \mathbf { i } + ( 1 + \mathrm { t } ) \mathbf { k } , - \pi / 2 < \mathrm { t } < \pi / 2$$

Multiple Choice

Find the curvature of the curve r(t) .
- $$\mathbf { r } ( \mathrm { t } ) = ( 3 + \ln ( \sec t ) ) \mathbf { i } + ( 1 + \mathrm { t } ) \mathbf { k } , - \pi / 2 < \mathrm { t } < \pi / 2$$

A) $\kappa = - \cos t$
B) $\kappa = \sin t$
C) $\kappa = \cos t$
D) $\kappa = 1 - \cos t$