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Solving Angles

  • Thread starter thomas49th
  • Start date
  • #1
655
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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 im not sure where to go from there.

Thanks
 
Last edited:

Answers and Replies

  • #2
HallsofIvy
Science Advisor
Homework Helper
41,794
925

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 im not sure where to go from there.

Thanks
How about subtracting 30 from both sides?
 
  • #3
HallsofIvy
Science Advisor
Homework Helper
41,794
925

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 im not sure where to go from there.

Thanks
What do you get if you subtract 30 from both sides?
 
  • #4
655
0
a = 6.8....
so

a = 6.8, 180 - 6.869..,
a = 6.8 and 173.1...
is that my final answer?
 
  • #5
Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
12,098
129
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
 

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