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# PROGRAM TO SOLVE

## PROGRAM TO SOLVE

(OP)

Dear all,
I am having difficulty in solving this problem in c++.
1/sqrt(f)=2*log10(Re*sqrt(f))/2.51
It is required to calculate f. Re is given as 128592.72.

Thanks.

Kunletee

### RE: PROGRAM TO SOLVE

Both sides are monotonous functions of F. Rearrange it:
0= 2*log10(Re*sqr(F))-2.51/sqr(F) ;  Replace 0 with Y.

Select an arbitrary value for F and calculate Y
Change it with dF and recalculate. Put a straight line
across these two points - solve its zero xing.

Replace this into F and repeat until Y=0

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