# Derive Formulas: Is it Necessary?

• marmot
In summary, the conversation discusses the importance of understanding the derivations of formulas in physics, although it is not necessary to memorize them. It is suggested to try deriving formulas on your own and fill in any gaps in knowledge over time. This will lead to a better understanding and appreciation of the subject matter.
marmot
is it necessary to know where to derive all my formulas, as a general rule? i always try to follow them and understand more or less where they came from, because i hate hand waving. i can derive a good chunk of them, especially the ones of mechanics, but some of the messier ones, like the ones of thermo or em sometimes go over my mind. i can tell you where most of the ones i don't know how to derive come from, but not do the derivation itself. should i try to memorize them?

I'm sure you can get by in the class without knowing how to derive all of the formulas, but part of truly understanding the material is in the derivations. So I guess it depends on whether you enjoy the subject matter enough.

i actually kn ow i don't have to know them to go by the class. but do professors for example, actually remember all those thrifty derivations?

You don't need to memorize the derivations, but you should understand the steps that are used. That's what physics is all about.

Here is a good strategy you may want to try:

Whenever you come across something you don't understand from basic principles, give a good shot at deriving it yourself. If it's taking too long and you aren't getting anywhere, make a note of it in the back of your mind and move on. When you learn new things, always be looking to fill in these old gaps.

For example, in a middle school science class I was told that the angle between atoms in a tetrahedron shape is 109.47... degrees. I tried hard but I absolutely could not figure out how to derive it. Then a year or so later when I learned trigonometry, I gave it a second thought and figured out how to solve it. Then a few years later I learned about vectors, gave it a third thought, and figured out how to solve it another way. Then years later in college I started talking about this with a friend, and he showed me yet another more elegant way to derive it.

If you are always filling in the old gaps in your knowledge, you will find that these sorts of convenient occurences happen all the time, and eventually you will have answers to your questions. It may take years, but it will happen.

## 1. What is the purpose of deriving formulas?

The purpose of deriving formulas is to mathematically express the relationship between different variables in a scientific phenomenon or process. It allows scientists to make predictions and understand the underlying principles of a system.

## 2. Is it necessary to derive formulas in science?

Deriving formulas is not always necessary, but it can greatly enhance our understanding and ability to make accurate predictions in science. In some cases, existing formulas may already describe a phenomenon accurately, but in other cases, deriving new formulas can lead to new discoveries and insights.

## 3. How do scientists derive formulas?

Scientists use a combination of mathematical techniques, such as differentiation and integration, to derive formulas. They also use empirical data and observations to test and refine their derived formulas.

## 4. Can derived formulas change over time?

Yes, derived formulas can change over time as new data and discoveries are made. Scientists may refine or revise formulas based on new evidence or theories, leading to a better understanding of a phenomenon.

## 5. Are derived formulas always accurate?

No, derived formulas may not always be accurate. They are based on assumptions and simplifications of real-world phenomena, and therefore may not account for all variables or unexpected factors. Scientists must continue to test and refine their formulas to improve their accuracy.

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