Find all solutions of sin on the interval

In summary, the conversation is about solving the equation 7sin(2x)-13sin(x)=0 for all solutions between 0 and 2pi. The person attempted to use the double angle formula for sin(2x)=2sin(x)cos(x) but got stuck towards the end. They were able to find the common factor of sin(x) in the final equation and ultimately found the solutions to be x=pi, 0.3801, and 5.9028.
  • #1
nickb145
68
0

Homework Statement



i have

solve 7sin(2x)-13sin(x)=0
for all solutions 0≤X<2p
I used the double angle formula for sin(2x)=2sin(x)cos(x)


The Attempt at a Solution



I'm getting stuck near the end
7(2sin(x)cos(x)-13sin(x))
14sin(x)cos(x)-13sin(x)

now I am stuck
 
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  • #2
nickb145 said:

Homework Statement



i have

solve 7sin(2x)-13sin(x)=0
for all solutions 0≤X<2p
I used the double angle formula for sin(2x)=2sin(x)cos(x)


The Attempt at a Solution



I'm getting stuck near the end
7(2sin(x)cos(x)-13sin(x))
14sin(x)cos(x)-13sin(x)

now I am stuck

What you wrote aren't equations. An equation must have two sides separated by an '='. In this case, your right hand side (RHS) equals 0.

In that final equation, can you find a common factor between the two terms?
 
  • #3
Curious3141 said:
What you wrote aren't equations. An equation must have two sides separated by an '='. In this case, your right hand side (RHS) equals 0.

In that final equation, can you find a common factor between the two terms?

That is what i am trying ot figure out. I would just say sin(x) could be factored out.

the 14sin and the 13sin are just throwing me off.
 
Last edited:
  • #4
Yep that was it. found the solutions. it was sin(x) that was the common factor. sin(x)=0 and cos(x)=13/14

x= pi, 0 .3801 and 5.902
 

What does it mean to "find all solutions of sin on the interval"?

Finding all solutions of sin on the interval means finding every possible value for the sine function within a given interval. This can be done by using mathematical techniques such as graphing or solving equations.

Why is it important to find all solutions of sin on the interval?

It is important to find all solutions of sin on the interval in order to fully understand the behavior of the sine function and to accurately solve trigonometric equations involving sine.

What is the interval in this context?

The interval refers to a specific range of values for the independent variable (typically represented by x) in a given function. In this case, it is the range of values for which we are finding solutions for the sine function.

What are the different methods for finding all solutions of sin on the interval?

Some common methods for finding all solutions of sin on the interval include graphing, using trigonometric identities, and solving equations using algebraic techniques. The specific method used will depend on the given problem and the level of accuracy required.

Can there be an infinite number of solutions for sin on the interval?

Yes, there can be an infinite number of solutions for sin on the interval. This is because the sine function is a periodic function, meaning it repeats itself infinitely. Therefore, there will always be an infinite number of solutions within any given interval.

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