trig identity used in integration by parts.

[Sonal7]

I am half way through watching this explanation of integration of sin^-1 x but I cant understand where sqrt (1-x^2) came from? I know hes using the trig identity
sin^2 x + cos^2 X =1, but I cant figure would the sqrt root of the x.
Confused!
Its at 2.14 min.

 

[Harry_the_cat]

Can you tell us how far into the video that bit is?

 

[Sonal7]

I got it now I think its using y= sin^-1 x then
using implicit differentiation.

 

[Sonal7]

Can you tell us how far into the video that bit is?

2.14 min

 

[Sonal7]