# Tutor profile: Rob O.

## Questions

### Subject: Pre-Calculus

What is the point of polar coordinates?

It is easy to assume that the only way to organize points is by using (x,y), the distance up and to the side from a given point of reference. But that's not always the best way to think about a location. Imagine standing at some starting point. You know what direction you want to go (the angle in the polar coordinate), and how far (the r in it) and those two values will land you at a specific unique location. And with certain kinds of graphs, such as circles and ellipses, it is fundamentally easier to describe them using (r,angle) than by marking off squares on the coordinate plane (x,y).

### Subject: Geometry

How do I know which Trig function to use in this triangle?

In trigonometry, it's all about ratios. The whole study of right triangle trig is not about formulas but about the fact that for a given angle there is a known ratio for a given pair of sides. So your first step, always, is to figure out where that angle is, and which two sides you're looking at. Find the angle you know or want to know. The side opposite of the angle is called the Opposite, the side next to it is called the Adjacent, and the longest side, the one across from the 90 degree angle is always the Hypotenuse. Once you know your two sides (and you will always be working with two of them) you pick the ratio that ties those two together.

### Subject: Algebra

How do I know what I'm supposed to do next in an Algebra Problem?

Algebra problems are like onions, cakes and ogres: They have layers. Your goal is to strip away the layers until all that's left on one side of the equation is the unknown. So you're always going to ask yourself, "what can I peel off now to get that variable alone? What's the next layer of this onion?" And the second key is to always remember that you need to keep the equation balanced. Imagine the problem is sitting on a scale with the equals sign in the middle at the balance. If you cut one side of the scale in half, you need to cut the other side in half to keep the scale from tipping over.

## Contact tutor

needs and Rob will reply soon.