which 1? didnt ya buy the book?
7aii)
I(y0->y) dy/sqrty = -k/A I(0->t) dt
...
sqrty = sqrty0 - kt/2A
make k/2A subject, (y=0, t=T)
integrate dt/dy from part i) to get a value for t
substitute k/2A and factorise
bii) triangles OP0P1 and OP1P2 are congruent (SAS)
.'. angles P0OP1 and P1P2P0 are equa;
.'. O, P0, P1, P2 are concylclic (converse of eqaul angle in the same segment )