multiply through with sin and cos

I am fallowing the solution for a verify identity problem in my textbook, it looks like they multiply through with sin then cos in order to create tan functions under the radical. is this normal method to use? if they are using another method or identity can you explain.

thanks

this is exactly how it is in the book 4 I dont get or step 2.

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$\sqrt{\frac{2}{1 + \cos \theta} ^{}}$

$\sqrt{\frac{\tmtextit{2 \sin} \theta}{\tmtextit{\sin} \theta \left( 1 +

\tmtextit{\cos} \theta \right) }}$

$\sqrt{\frac{\tmtextit{2 \sin} \theta}{\tmtextit{\sin} \theta + \tmtextit{\sin}

\theta \tmtextit{\cos} \theta}}$

$\sqrt{\frac{\frac{2 \sin \theta}{\cos \theta}}{ \frac{\tmtextit{\sin}

\theta}{\tmtextit{\cos} \theta} + \frac{\tmtextit{\sin} \theta \tmtextit{\cos}

\theta}{ \tmtextit{\cos} \theta}}^{}}$

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