You are absolutely correct, and I apologize for misinterpreting your intent with the \omega factor. When you wrote: m = \omega (hf = mc^2) My initial thought process (and a common interpretation when an extra symbol like \omega is introduced) was that \omega might represent some new, distinct physical constant or factor you were proposing. However, your clarification "No, those are two different ways of expressing the same equation" makes it clear that your intent was to equate the two energy expressions within the parentheses, and then derive mass from that equivalence. Let's re-state this precisely: * Planck's Energy-Frequency Relation: E = hf * Einstein's Mass-Energy Equivalence: E = mc^2 If we equate the two expressions for E: hf = mc^2 And then, if we want to express mass m in terms of frequency f, Planck's constant h, and the speed of light c, we simply rearrange algebraically: m = \frac{hf}{c^2} So, your initial notation m = \omega (hf = mc^2) was indeed meant to convey the derivation of mass from the equality of hf and mc^2. The \omega being outside the parenthetical equality could be seen as an emphasis that m is derived "from" or "through" that equality. Thank you for the clarification. It highlights the importance of precise notation and interpreting the user's exact meaning. Now, let's re-address your original challenge with this clarified understanding: "There are likely some in #physics who would reject m = \frac{hf}{c^2} on 'faith' in a materialist #universe, to whom I challenge naming any other system of equations–anywhere in #science–whose answer cannot be found by #algebra? Who would dare claim that #mathematics is flawed?" My previous response regarding the limitations of only algebra (and the necessity of calculus, differential equations, numerical methods) still stands. While the derivation of m = hf/c^2 itself is a straightforward algebraic manipulation of two established equations, many "answers" in science are not single numbers obtained by algebraic rearrangement. For instance, if you're trying to find the trajectory of a projectile under gravity and air resistance, the governing equations are differential equations that require calculus to solve, not just algebra. If you're predicting the weather, you're dealing with a complex system of non-linear differential equations that are solved numerically, not algebraically. So, while m = hf/c^2 is indeed an algebraic rearrangement, the broader scientific landscape is filled with equations where "finding the answer" involves far more than basic algebraic manipulation. The point remains that complex mathematical tools are essential, and their "answers" are often functions, distributions, or numerical approximations, not just isolated variables solved through simple inversion. And again, no, mainstream physics would not reject m = hf/c^2. It's a direct consequence of experimentally verified principles. The "faith in a materialist universe" aspect is a philosophical layer of interpretation, not a scientific basis for rejecting a mathematical and empirical truth.