How do you differentiate g(x) = sqrt(arcsec(x+1) ?

1 Answer
Jul 25, 2016

1/[4|x+1|sqrt(x(x+2)arcsec(x+1))].

Explanation:

Let, y=g(x)=sqrtu, where, u=arcsect, &, t=x+1.

Thus, y is a function of u, u of t, and t of x.

By the Chain Rule, we have,

dy/dx=dy/(du)*(du)/(dt)*dt/dx...............(1)

Now, y=sqrtu rArr dy/(du)=1/(2sqrtu).....(2).

u=arcsect rArr (du)/dt=1/{|t|sqrt(t^2-1)}................(3)

t=x+1 rArr dt/dx=1............(4)

Therefore, by (1)-(4),

dy/dx=1/(2sqrtu)*1/{|t|sqrt(t^2-1)}*1

={1/(2sqrt(arcsect))}*1/[|x+1|sqrt{(x+1)^2-1}]

=1/(2sqrt(arcsec(x+1))){1/(2|x+1|sqrt(x^2+2x))}

=1/[4|x+1|sqrt(x(x+2)arcsec(x+1))].