Find all solutions of sin on the interval

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SUMMARY

The discussion focuses on solving the equation 7sin(2x) - 13sin(x) = 0 for all solutions in the interval 0 ≤ x < 2π. The double angle formula sin(2x) = 2sin(x)cos(x) is utilized, leading to the equation 14sin(x)cos(x) - 13sin(x) = 0. The common factor sin(x) is identified, resulting in the solutions sin(x) = 0 and cos(x) = 13/14. The final solutions are x = π, 0.3801, and 5.902.

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nickb145
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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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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?
 
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:
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
 

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