A technique similar to rationalizing the denominator can be used to transform some rational trigonometric expressions to different forms. For example, multiply numerator and denominator of $\frac { \operatorname { sin } ( \theta ) } { 1 + \operatorname { cos } ( \theta ) }$ by $1 – \cos\left(θ\right)$ and rewrite the expression in terms of sine and cosine. Now rewrite the expression in terms of other trig functions.