for ci i used simultaneous equations with the two curves because they could both be rearranged to be in terms of xsquared and then just simplified. but ii i dont know how it couldve been >1/2
i got all of q16 apart from cii. i reckon the paper mighta been wrong because i rearranged to find r, and made r>0 as the question said, and i got c>1/4 not c>1/2. did anyone get the right answer?? if so how??