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sin(x/2)=-1/2

sin(x/2)=-1/2 equation

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Numerical solution:

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The solution

You have entered [src]
   /x\       
sin|-| = -1/2
   \2/       
$$\sin{\left(\frac{x}{2} \right)} = - \frac{1}{2}$$
Detail solution
Given the equation
$$\sin{\left(\frac{x}{2} \right)} = - \frac{1}{2}$$
- this is the simplest trigonometric equation
This equation is transformed to
$$\frac{x}{2} = 2 \pi n + \operatorname{asin}{\left(- \frac{1}{2} \right)}$$
$$\frac{x}{2} = 2 \pi n - \operatorname{asin}{\left(- \frac{1}{2} \right)} + \pi$$
Or
$$\frac{x}{2} = 2 \pi n - \frac{\pi}{6}$$
$$\frac{x}{2} = 2 \pi n + \frac{7 \pi}{6}$$
, where n - is a integer
Divide both parts of the equation by
$$\frac{1}{2}$$
we get the answer:
$$x_{1} = 4 \pi n - \frac{\pi}{3}$$
$$x_{2} = 4 \pi n + \frac{7 \pi}{3}$$
The graph
Rapid solution [src]
     -pi 
x1 = ----
      3  
$$x_{1} = - \frac{\pi}{3}$$
     7*pi
x2 = ----
      3  
$$x_{2} = \frac{7 \pi}{3}$$
x2 = 7*pi/3
Sum and product of roots [src]
sum
  pi   7*pi
- -- + ----
  3     3  
$$- \frac{\pi}{3} + \frac{7 \pi}{3}$$
=
2*pi
$$2 \pi$$
product
-pi  7*pi
----*----
 3    3  
$$- \frac{\pi}{3} \frac{7 \pi}{3}$$
=
     2
-7*pi 
------
  9   
$$- \frac{7 \pi^{2}}{9}$$
-7*pi^2/9
Numerical answer [src]
x1 = 45.0294947014537
x2 = -17.8023583703422
x3 = -63.8790506229925
x4 = 49.2182849062401
x5 = 19.8967534727354
x6 = -13.6135681655558
x7 = -26.1799387799149
x8 = -30.3687289847013
x9 = 195.825942073764
x10 = 57.5958653158129
x11 = 74.3510261349584
x12 = -93.2005820564972
x13 = -5.23598775598299
x14 = -76.4454212373516
x15 = 32.4631240870945
x16 = -42.9350995990605
x17 = 36.6519142918809
x18 = 479288.705614517
x19 = -38.7463093942741
x20 = -51.3126800086333
x21 = -68.0678408277789
x22 = 61.7846555205993
x23 = 70.162235930172
x24 = -1.0471975511966
x25 = 99.4837673636768
x26 = 95.2949771588904
x27 = -55.5014702134197
x28 = 82.7286065445312
x29 = -80.634211442138
x30 = 7.33038285837618
x31 = -3762.58080144938
x32 = -101.57816246607
x33 = 11.5191730631626
x34 = 24.0855436775217
x35 = 86.9173967493176
x36 = -89.0117918517108
x36 = -89.0117918517108
The graph
sin(x/2)=-1/2 equation