Problems-II: exact value of cos(u/2) when 3pi < u < 7pi/2 and tan(u) = sqrt[5]/2

[pwndogmaster1]

Problems-II: exact value of cos(u/2) when 3pi < u < 7pi/2 and tan(u) = sqrt[5]/2

Here's a few problems you can give a shot at.
1.
2.
3.

4.

 

[Deleted member 4993]

Here's a few problems you can give a shot at.
1.
2.
3.

4.

Please post 1 problem in one thread!

What are your thoughts?

If you are stuck at the beginning tell us and we'll start with the definitions.

Please share your work with us ... even if you know it is wrong

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...Before-Posting

 

[stapel]

exact value of cos(u/2) when 3pi < u < 7pi/2 and tan(u) = sqrt[5]/2

What are your thoughts? What have you tried? How far have you gotten? Where are you stuck?

For instance, you noted the quadrant for u, recalled the half-angle identity for cosine, and... then what?

Please be complete. Thank you!