How to solve this problem?
Find sin(x/2) if sin(x)= -0.4 and 3pi/2 < or equal to (x) < or equal to 2pi
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using your calculator,
take inverse of sine with argument (-0.4)
arcsin(-0.4)…
this gives you an angle “A”…. which should be negative….
note:
A is an angle between 0 and -90 (or pi/2), which is the same at between 3pi/2 and 2pi.
I guess they want you to make the angle between 3pi/2 and 2pi.. or calculator will give you a negative angle….
so ADD 2pi to get an angle between 3pi/2 and 2pi.
take the new angle “B” and divide it by 2. ….
which should give you an angle between 3pi/4 and pi (2ND Quadrant)
take the sin(B/2) which will give you positive…. Sine is positive in the 2nd quadrant.
good luck.
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