How to change Nan value with zero and return them again?

I have a matrix like A which some of its members are NAN. I want to do some mathematical works on it, but I can not do it because of nan values. So I decided to change these nan values to zero and after finishing mathematical works return Nan to the same places( my matrix dimension doesn't change during the job.)

for example:

B=A.^(0.5) [it doesn't work because of nan values in A]

I should find nan values and replace them with zero to build a new A.

Now I use A.^0.5 with the A built in the last step for B=A.^2

I have B with the same dimension of A, I should return nan values to the same place of B which were replaced with zero in A.

How can I do it with Matlab features?

[I don't want to replace all zero values in B, I want to replace zero values in B which there were nan values in the similar position of A.] N

Answer 1

[Amit]

Ind = find(isnan(A));
A(ind) = 0;
B = A.^0.5;
B(ind) = NaN;

[Amit]

BTW, A.^0.5 would work even for NaN values.