1. The problem statement, all variables and given/known data (I haven't got the thing to write equations so this is a little difficult to understand sorry!) Show that the integral of (4x^2 - 1)^-1/2 from 0.625 to 1.3 is equal to 1/2(ln 5 - ln 2) 2. Relevant equations my formula book states: the integral of (x^2 - a^2)^-1/2 is arcosh (x/a) or ln (x + (x^2 - a^2)^1/2) 3. The attempt at a solution the original integral equals: 1/2 the integral of (x^2 - 1/4)^-1/2 comparing this to the stated result I get a^2 = 1/4 so substituting in limits: = 1/2 ln(1.3 + (1.3^2 -1/4)^1/2) - 1/2 ln(0.625 + (0.625^2 - 1/4)^1/2) =1/2 (ln 2.5 - ln 1) which is incorrect. I just about follow the worked solution, which uses a very slightly different method, but I want to know why this is incorrect because I can't find a mistake in it.. Thanks!