Related Rates? Problem

[sarahjohnson]

http://postimg.org/image/cxsm28w81/

(the problem ^)

At least I think this is a related rates problem...I'm not quite sure. Word problems confuse me. I have no idea where to get started. I think I should use a trig identity....but how do I use X and Y and R...

I also have no idea how to do the linear approximation part because we didn't go over that at all in class.

Please help!!

and thank you

 

[Deleted member 4993]

Hints: Drop a perpendicular from R onto PQ

PQ =1

QR = √2 * (1-x) ................. Why

Now continue....