Floating point operation is very inaccurate

[elvin-du]

`
C standard library referenced by POW function < math. H >，result as follows：

double ww = pow(3.0, 0.3) = 1.1293469354568555
double xx = pow(2.2, 0.3) = 1.029005759421095
float yy = powf(2, 0.3) = 1.2311444
float yy = powf(2.4, 0.3) = 1.3003594
long double zz = powl(2, 0.3) = 1
long double mm = powl(2.3, 0.3) = 1.04282000071553305
double aa = pow(1.12, 0.5) = 1.0583005244258363

result using Calculator as follows：

pow(3.0, 0.3) = 1.3903891703159093404852542946161
pow(2.2, 0.3) = 1.2668546920110241257762468650659
powf(2, 0.3) = 1.2311444133449162844993930691677
powf(2.4, 0.3) = 1.3003593134073364931694839670248‬
powl(2, 0.3) = 1.2311444133449162844993930691677
powl(2.3, 0.3) = 1.2838620180052701355554021438659‬
pow(1.12, 0.5) = 1.0583005244258362362006463014557
`