question about trigonometric function transformation what is the difference between 
$\cos^2(\theta - 180) $ and  $\cos^2(180 - \theta) $ Does $\\cosec^2(450 + \theta)$ transform into $\sec$?

$$cosec^2(450+\theta)=\frac{1}{sin^2(450+\theta)}\\= \frac{1}{sin^2(360+90+\theta)}=\\\frac{1}{sin^2(90+\theta)}=\\\frac{1}{cos^2(\theta)}$$
