# Tutor profile: Melody W.

## Questions

### Subject: Chemistry

What is a reducing agent and how does it differ from a oxidizing agent?

A reducing agent is a substance that causes reduction by losing its electrons and therefore it becomes more oxidized (more positive). In contrast, a oxidizing agent is a substance that causes oxidation by gaining electrons and becomes more reduced (more negative). Remember that a reducing agent is NOT reduced and an oxidizing agent is NOT oxidized.

### Subject: Biology

Identify the four elements that make up 96% of living matter?

These elements would be carbon, hydrogen, oxygen, and nitrogen. A great way to remember this is to use CHON, a mnemonic.

### Subject: Calculus

If f(x) = -x^3 + 3x, what is the derivative, f'(x)?

Taking f(x) = -x^3 + 3x, in order to get the derivative, we would bring down the exponent of 3 and subtract 1 from that exponent to give -3x^2. For the 3x in the original equation we would simply do the same, however, the exponent here is 1. We would again bring down the 1 and multiply it by the 3 in front of the x to give us 3. We would then subtract 1-1 for the exponent and that would give us 0 and x^0 is equal to 1. This would result in a final answer of f'(x) = -3x^2 + 3.

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