Consider the given integral.
I=∫x√4−x2dx
Let t=4−x2
dtdx=0−2x
−dt2=xdx
Therefore,
I=−12∫1√tdt
I=−12(2√t)+C
I=−√t+C
On putting the value of t, we get
I=−√4−x2+C
Hence, this is the answer.