a maths help急要

1.)

y = tanx/x
xy = tanx
d(xy)/dx = d(tanx)/dx
xdy/dx + y = sec^2 x
xdy/dx + y = 1 + tan^2 x
xdy/dx + y = 1 + [x(tanx/x)]^2
xdy/dx + y = 1 + (x^2)(y^2)



2.)
其實呢題唔知你想問乜

咁唯有D左佢啦=.=...再加多幾步

y=tan^2 x

dy/dx
= 2tanx sec^2 x
= 2tanx(1+tan^2 x)
= 2(√y)(1+y)