Trig identities, exact values

Hey, I was absent the day my class went over how to solve these problems. So I was wondering if I could get some help.

-Use the fundamental identities to find the exact values of the remaining trig functions of x...

1)cos x= square root 7/4 and cot x= - square root 7/3

Would the sec x= 1/square root 7/4...? Or is that not the way to think of it?

-Simplify each expression using the fundamental identities

2) Sec theta X cos theta

3) 1/csc^2x + 1/sec^2x

4) 1-sin^2u/cosu

5) cos^2x+ (sin x +1)^2/sin x + 1

Thank you so much if you can help me. Also, is there a chat room or anything of the sort on this site, I'm new.

:)

-and yes, I'm horrible at math haha