The phrase "a useful approximation and" is correct and usable in written English.
It can be used when discussing a method, calculation, or model that provides a close estimate of a value or outcome, often in scientific or mathematical contexts.
Example: "In many cases, using a useful approximation and simplifying the equations can lead to quicker solutions without sacrificing too much accuracy."
Alternatives: "a helpful estimate and" or "a practical approximation and".
In materials science, this is a useful approximation for semi-conductors and a very good approximation for metals at room temperature.
The C + NVC model with the incorporation of Wu et al. (2009) outputs was adapted for use in this paper, it was shown to give a useful approximation of the difference between scenarios, and could be further utilised with specific wildfire management data (i.e. pre-suppression efforts–such as prescribed burning) if and where available.
It can exactly transform a SH-wave propagation problem posed for a medium with spherical symmetry into a problem posed for a plane-stratified medium and give a useful approximation to a P-SV problem in a spherically symmetric medium.
The initial rate of development of constitutional undercooling is shown to be equivalent to the growth restriction factor and is a useful approximation for the effect of solute on grain size when potent nucleant substrates are present.
This remains a useful approximation even for cases where T and τ exhibit more complex dependencies on myosin concentration or where they are independently regulated (see below).
These models rendered a useful approximation for binding requirements in the BBB-choline transporter and, until such time as the cloned transporter becomes available, may have significant utility in developing a predictive model for the rational design of drugs targeted to the brain.
Although this exact cancellation of the radial and angular dispersion effects provides a useful approximation for many types of proton pairs, the 3-fold rotational jumps of methyl protons deviates strongly from spherical isotropy.
These assumptions are not too restrictive and the solution appears to be a useful approximation for a broad range of material-mill combinations.
