Solving the Function y=sin2x +cos3x

[Venito]

Homework Statement

Consider the function y=sin2x +cos3x

A.] Find a value for y if x= pie radians.

B.] Find y if x= 0.3 radians.

C.] What is the period of this function? Show how you obtained your answer?

The Attempt at a Solution

What I would like to know is how would I go about doing this question.

That is all.

I am very fuzzy with doing any of this work, and would like to know how to best tackle the problem.

Cheers.

 

[Mark44]

Homework Statement

Consider the function y=sin2x +cos3x

A.] Find a value for y if x= pie radians.

B.] Find y if x= 0.3 radians.

C.] What is the period of this function? Show how you obtained your answer?

The Attempt at a Solution

What I would like to know is how would I go about doing this question.

That is all.

I am very fuzzy with doing any of this work, and would like to know how to best tackle the problem.

Cheers.

First off, pie is a kind of dessert food, and pi is the name of the Greek letter.

For the first two parts, do you know how to evaluate a function? That is all that is being asked in a and b.

For the third part, you need to know the periods of sin(2x) and cos(3x), and then find the smallest value that both periods evenly divide.

 

[Jerbearrrrrr]

For A and B:
Write out y but with the given value of x substituted in. You then just have to do the 'adding up'.
For B you need a calculator. Do A with a calculator if you want, and see if you can use any facts you've learned to figure out why it's such a simple number

C is a bit trickier.
Do you know what the period of a function is?

 

[Venito]

I use to know but far to rusty. And don't have my old books to look at.

So no don't remember the period of the function.

mac

 

[Mark44]

This is exactly the same question you posted back in August of last year - https://www.physicsforums.com/showthread.php?t=332587. We have given you some advice on how to proceed on the first two parts, so have at it. For the third part you need to expend some effort (like getting a book or doing an internet search) to help yourself.

 

[berkeman]

I use to know but far to rusty. And don't have my old books to look at.

So no don't remember the period of the function.

mac

The period of a sine wave is just where the waveform repeats. So one period is one cycle of the sine wave:

http://en.wikipedia.org/wiki/Sine_wave

As stated, your previous thread would seem to have helped you to figure out the first 2 questions.

In the 3rd part of this problem, you need to figure out where the 2 sinusoid waves cross the x-axis for the repeated pattern.