Cambridge 4I Q17 a) and c) (1 Viewer)

[ISAM77]

The enrichment questions always make me feel inadequate.

I can't figure out part a).

b) is done .

 

[ISAM77]

Why does du = (1+t^-2) dt

 

[ISAM77]

My brain is fried. Uh. such a silly thing to get stuck on. Literally 2u stuff