2. 1

3.√2/2

4. 1/3

5.( 1)x=2, so the original formula =7/8.

(2) let m/n=k, because m >；; N, so k> 1

Then k 2-6k+ 1 = 0.

k=3+2√2

If you don't understand, you can ask and hope to adopt it.