Solving for a in 5sin(a+30)=3

  • Thread starter thomas49th
  • Start date
In summary, the values of a for the interval 0 <= a <= 360 where 5sin(a+30) equals 3 are 6.8 and 173.1. It is important to double check the solutions by substituting them back into the original equation.
  • #1
thomas49th
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0

Homework Statement



find the values of a to 1 decimal place for the interval 0 <= a <= 360 for which

5sin (a+30) = 3

The Attempt at a Solution


I know this is really easy but I've forgotten the method :(somthing like

(a + 30) = arcsin(3/5)
a + 30 = 36.869...

but I am not sure where to go from there.

Thanks
 
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  • #2
thomas49th said:

Homework Statement



find the values of a to 1 decimal place for the interval 0 <= a <= 360 for which

5sin (a+30) = 3


The Attempt at a Solution


I know this is really easy but I've forgotten the method :(


somthing like

(a + 30) = arcsin(3/5)
a + 30 = 36.869...

but I am not sure where to go from there.

Thanks

How about subtracting 30 from both sides?
 
  • #3
thomas49th said:

Homework Statement



find the values of a to 1 decimal place for the interval 0 <= a <= 360 for which

5sin (a+30) = 3


The Attempt at a Solution


I know this is really easy but I've forgotten the method :(


somthing like

(a + 30) = arcsin(3/5)
a + 30 = 36.869...

but I am not sure where to go from there.

Thanks

What do you get if you subtract 30 from both sides?
 
  • #4
a = 6.8...
so

a = 6.8, 180 - 6.869..,
a = 6.8 and 173.1...
is that my final answer?
 
  • #5
Looks good, how about checking those numbers back in the original equation? Then you can be sure.

I.e., does 5sin(6.869+30) equal 3? And similarly for 173.131
 

What does the equation 5sin(a+30)=3 mean?

The equation 5sin(a+30)=3 is a mathematical expression that represents the relationship between the sine of an angle (a+30) and the number 3. It is asking to solve for the value of a that makes the equation true.

How do I solve for a in this equation?

To solve for a, you will need to use algebraic manipulation and trigonometric identities. First, isolate the sine term by dividing both sides by 5. Then, use the inverse sine function to find the value of (a+30). Finally, subtract 30 from both sides to find the value of a.

Can I use a calculator to solve this equation?

Yes, you can use a calculator to solve this equation. However, make sure your calculator is set to the correct mode (degrees or radians) and that you are using the inverse sine function to find the value of (a+30).

Are there multiple solutions for a in this equation?

Yes, there are multiple solutions for a in this equation. This is because the sine function has a periodic nature and can have multiple angles that produce the same value. You will need to use the general solution, which involves adding or subtracting integer multiples of 360 degrees or 2π radians to the initial value of (a+30).

How can I check if my solution is correct?

You can check your solution by substituting the value of a into the original equation and seeing if it produces the number 3. You can also graph the equation and see if the resulting point lies on the curve.

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