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# Help with Trig question watch

1. Solve the equation 1+3sin(x)=2 for 0<x<360
2. (Original post by dan_585)
Solve the equation 1+3sin(x)=2 for 0<x<360
What part are you struggling with?
3. Rearrange for sin(x)
3sin(x) = 1
sin(x) = 1/3

Use your CAST diagram to find positive roots, which are the 1st and 2nd quadrants

First root is simply arcsin(1/3) and then the second root is 180 - arcsin(1/3)

If the root was within the 3rd quadrant you'd do 180 + arcsin(1/3)
If the root was within the 4th quadrant you'd do 360-arcsin(1/3)

Plotting a rough sin graph can be useful for visualising these concepts
4. (Original post by CompSci in2k17)
Rearrange for sin(x)
3sin(x) = 1
sin(x) = 1/3

Use your CAST diagram to find positive roots, which are the 1st and 2nd quadrants

First root is simply arcsin(1/3) and then the second root is 180 - arcsin(1/3)

If the root was within the 3rd quadrant you'd do 180 + arcsin(1/3)
If the root was within the 4th quadrant you'd do 360-arcsin(1/3)

Plotting a rough sin graph can be useful for visualising these concepts

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