Ive attached the question and the answer to part ii
Im not sure why rx=t
Hey!
Great question, as the explanation isn't great. Basically, it's just an algebraic trick that let's us use the results from part i) in part ii)!
We know that a solution to
is approximately 0.56 from part i). This holds true for any value of t: ie. for any formula e to the power of x equals 1 over x, a rough solution is 0.56. We therefore know that a solution to the equation
also has a solution at
however it may be tough for some students to see exactly why (the fact that this is the same equation as the one in part i)). Therefore, the answers let rx = t to make it visually easier to see why the answer translates.
I hope this makes sense; it's a little profound, but once you've wrapped your head around it it makes sense.
Jake