So, I've been having issues with my homework. My teacher was gone for the class and posted up videos, but both the videos and the book don't really go over a number of the problems. I'm having issues with a few, and I was wondering if somebody could guide me through them step by step.

Anyways, here are the ones I was having problems with:

Find sin 2x, cos 2x, and tan 2xfrom the given information. csc= 7, tanx< 0x

Simplify the expression by using a Double-Angle Formula or a Half-Angle Formula.

a) cos^{2}θ/2 -sin^{2}θ/2b) 2 sinθ/2cosθ/2Evaluate the expression under the given conditions. sin 2

θ; sinθ= 1/5,θin Quadrant II

Find the value of the sum

cosπ/12+ cos7π/12

Sorry it's quite a lot, but it's new information and I 'm having a hard time without a professor around to answer my questions.