# Courses How much trigonometry is used in high level math?

1. Oct 28, 2016

### ScienceMan

Hi all. I'm a liberal arts graduate looking to enter a statistics masters program (in case it matters). I'm retaking some lower level courses to prove I can do math I wanted to know how much trig is used in Calc II and beyond. I didn't do great in that class (I'm gonna retake it) and when I took Calc I I didn't need to know much trig. They just taught us to take the derivatives of the trig functions and honestly I probably didn't even need the right triangle trig you learn in high school algebra or physics. The fact I had no idea how to do identities or anything beyond knowing sine, cosine, and tangent didn't harm me at all. Does that change after Calc I?

2. Oct 28, 2016

### Staff: Mentor

Trig functions are probably of less interest in Calc and Statistics. On the other hand, one simply expects the fundamental formulas and meanings to be known, as basic multiplications should be known. E.g. the scalar or dot product is important and has to do with angles. These basics, however, can easily be looked up on Wikipedia (if there is time for it). And on concepts like Fourier transformations and / or integrals of trig functions, it is convenient to have the standards at hand without to have them looked up. It's with all the basics: nobody will ask you to learn them, it's assumed that you already have. To draw a line between standard knowledge and exotic formulas is difficult by nature. So to have a read on the sine, cosine and tangent pages on Wikipedia is likely a good idea. If you don't understand them, you could ask specific questions here, but to hope for a general answer "not important at all" would do you no favor.

3. Oct 29, 2016

### symbolipoint

You need to review Trigonometry very thoroughly because Calculus II and III use ALL of what you studied already from your Trigonometry course.

4. Oct 29, 2016

### Staff: Mentor

I agree with this statement with regard to statistics, but disagree in regard to calculus. Some of the first differentiation formulas one typically learns are the formulas for the derivatives of sin(x), cos(x), tan(x), and the other three, as well as the derivatives of the inverse trig functions. Later, in the study of integrals, trig substitutions are an important tool in evaluating integrals such as $\int \sqrt{x^2 + 4} dx$ and the like. And then when you study infinite series, there are the Maclaurin series for sin(x) and cos(x) and others. In the study of Fourier series, you're looking at sums of terms like sin(nx) and cos(nx).

In summary, I would say that trig gets used a lot in calculus, but much less or not at all in statistics.

5. Oct 29, 2016

### Student100

And LA, ODE's, PDE's, it never really goes away. I wouldn't let not doing the greatest in trig deter me from carrying on though. Eventually you'll use trig functions so much they become second nature.