## Convenience and test functions

All the convenience functions are designed to facilitate a computational environment where the user does not need to worry about relative errors. The functions seem to be pointless at first sight, but behind their codes, there are state-of-the-art ideas that offer faster and more reliable results.

We have convenience functions beyond the ones defined in the NumPy libraries to find the solutions of trigonometric functions in degrees (`cosdg`

, `sindg`

, `tandg`

, and `cotdg`

); to compute angles in radians from their expressions in degrees, minutes, and seconds (`radian`

); common powers (`exp2`

for *2**x*, and `exp10`

for *10**x*); and common functions for small values of the variable (`log1p`

for *log(1 + x)*, `expm1`

for *exp(x) - 1*, and `cosm1`

for *cos(x) - 1*).

For instance, in the following code snippet, `the log1p`

function computes the natural logarithm of *1 + x*. Why not simply add 1 to the value of *x* and then take the logarithm instead? Let's compare:

>>> import numpy>>...