# Homework Help: A Odd Radian Question.

1. Aug 25, 2009

### Venito

1. The problem statement, all variables and given/known data
Consider the function y=sin2x +cos3x.

a.] Find a Value for the y if x= pye [Or who how ever it is spelled. 3.141592654]

b.] Find y if x=0.3 Radians.

c.] What is a period of this function? Show how you obtain this answer.

3. The attempt at a solution

No attempt since I have never come across these types of question in Radians before.

2. Aug 25, 2009

### tiny-tim

Hi Venito!

(have a pi: π )

if you're not used to radians, do it in degrees, and convert using the 180/π factor.

3. Aug 25, 2009

### Venito

I am use to radians. Just not these. So use degrees. Okay I will give it a try.

Thanks.

4. Aug 25, 2009

### Staff: Mentor

The period of sin(2x) is π radians. The period of cos(3x) is 2π/3 radians. The period of the sum of these two functions is the smallest interval that is evenly divisible by both π and 2π/3.

By the way, we spell the name of this Greek letter as pi. I'm guessing that you're Italian, and it is spelled the same way in Italian.

5. Aug 25, 2009

### HallsofIvy

You certainly should know that $sin(2\pi)= 0$ and $cos(3\pi)= -1$.

This is not going to be any simple value. Use a calculator.

What is the period of sin(2x)? What is the cos(3x)? What is the least common multiple of those two periods? Do you see why that is the period of y?