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(2sin((3pi)/2+2x)^2+sin(4x))/log3(2^(1/2)*sinx)=0 equation

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Numerical solution:

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The solution

You have entered [src]
     2/3*pi      \               
2*sin |---- + 2*x| + sin(4*x)    
      \ 2        /               
----------------------------- = 0
     /   /  ___       \\         
     |log\\/ 2 *sin(x)/|         
     |-----------------|         
     \      log(3)     /         
$$\frac{\sin{\left(4 x \right)} + 2 \sin^{2}{\left(2 x + \frac{3 \pi}{2} \right)}}{\frac{1}{\log{\left(3 \right)}} \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}} = 0$$
Detail solution
Given the equation
$$\frac{\sin{\left(4 x \right)} + 2 \sin^{2}{\left(2 x + \frac{3 \pi}{2} \right)}}{\frac{1}{\log{\left(3 \right)}} \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}} = 0$$
transform
$$\frac{\left(\sqrt{2} \sin{\left(4 x + \frac{\pi}{4} \right)} + 1\right) \log{\left(3 \right)} - \log{\left(\sin{\left(x \right)} \right)} - \frac{\log{\left(2 \right)}}{2}}{\log{\left(\sin{\left(x \right)} \right)} + \frac{\log{\left(2 \right)}}{2}} = 0$$
$$-1 + \frac{\sin{\left(4 x \right)} + 2 \sin^{2}{\left(2 x + \frac{3 \pi}{2} \right)}}{\frac{1}{\log{\left(3 \right)}} \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}} = 0$$
Do replacement
$$w = \cos{\left(2 x \right)}$$
Given the equation:
$$-1 + \frac{\sin{\left(4 x \right)} + 2 \sin^{2}{\left(2 x + \frac{3 \pi}{2} \right)}}{\frac{1}{\log{\left(3 \right)}} \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}} = 0$$
Use proportions rule:
From a1/b1 = a2/b2 should a1*b2 = a2*b1,
In this case
a1 = (2*cos(2*x)^2 + sin(4*x))*log(3)

b1 = log(sqrt(2)*sin(x))

a2 = 1

b2 = 1

so we get the equation
$$\left(\sin{\left(4 x \right)} + 2 \cos^{2}{\left(2 x \right)}\right) \log{\left(3 \right)} = \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}$$
$$\left(\sin{\left(4 x \right)} + 2 \cos^{2}{\left(2 x \right)}\right) \log{\left(3 \right)} = \log{\left(\sqrt{2} \sin{\left(x \right)} \right)}$$
Expand brackets in the left part
2*cos+2*x^2 + sin4*x)*log3 = log(sqrt(2)*sin(x))

Expand brackets in the right part
2*cos+2*x^2 + sin4*x)*log3 = logsqrt+2sinx)

This equation has no roots
do backward replacement
$$\cos{\left(2 x \right)} = w$$
Given the equation
$$\cos{\left(2 x \right)} = w$$
- this is the simplest trigonometric equation
This equation is transformed to
$$2 x = \pi n + \operatorname{acos}{\left(w \right)}$$
$$2 x = \pi n + \operatorname{acos}{\left(w \right)} - \pi$$
Or
$$2 x = \pi n + \operatorname{acos}{\left(w \right)}$$
$$2 x = \pi n + \operatorname{acos}{\left(w \right)} - \pi$$
, where n - is a integer
Divide both parts of the equation by
$$2$$
substitute w:
The graph
Rapid solution [src]
     -3*pi
x1 = -----
       4  
$$x_{1} = - \frac{3 \pi}{4}$$
     -5*pi
x2 = -----
       8  
$$x_{2} = - \frac{5 \pi}{8}$$
     -pi 
x3 = ----
      4  
$$x_{3} = - \frac{\pi}{4}$$
     -pi 
x4 = ----
      8  
$$x_{4} = - \frac{\pi}{8}$$
     3*pi
x5 = ----
      8  
$$x_{5} = \frac{3 \pi}{8}$$
     7*pi
x6 = ----
      8  
$$x_{6} = \frac{7 \pi}{8}$$
x6 = 7*pi/8
Sum and product of roots [src]
sum
  3*pi   5*pi   pi   pi   3*pi   7*pi
- ---- - ---- - -- - -- + ---- + ----
   4      8     4    8     8      8  
$$\left(\left(\left(\left(- \frac{3 \pi}{4} - \frac{5 \pi}{8}\right) - \frac{\pi}{4}\right) - \frac{\pi}{8}\right) + \frac{3 \pi}{8}\right) + \frac{7 \pi}{8}$$
=
-pi 
----
 2  
$$- \frac{\pi}{2}$$
product
-3*pi -5*pi -pi  -pi  3*pi 7*pi
-----*-----*----*----*----*----
  4     8    4    8    8    8  
$$\frac{7 \pi}{8} \frac{3 \pi}{8} \cdot - \frac{\pi}{8} \cdot - \frac{\pi}{4} \cdot - \frac{3 \pi}{4} \left(- \frac{5 \pi}{8}\right)$$
=
      6
315*pi 
-------
 65536 
$$\frac{315 \pi^{6}}{65536}$$
315*pi^6/65536
Numerical answer [src]
x1 = 42.0188017417635
x2 = -31.8086256175967
x3 = 74.6128255227576
x4 = 29.0597320457056
x5 = -77.7544181763474
x6 = 34.164820107789
x7 = -21.2057504117311
x8 = 54.1924732744239
x9 = -47.5165888855456
x10 = -52.2289778659303
x11 = -69.9004365423729
x12 = 98.174770424681
x13 = 2.74889357189107
x14 = 43.5895980685584
x15 = 84.4303025652257
x16 = 90.7134878724053
x17 = 35.3429173528852
x18 = -63.6172512351933
x19 = -88.3572933822129
x20 = -44.7676953136546
x21 = -44.3749962319558
x22 = 4.31968989868597
x23 = 64.009950316892
x24 = 81.2887099116359
x25 = -75.7909227678538
x26 = -25.9181393921158
x27 = -91.4988860358027
x28 = -13.3517687777566
x29 = 13.7444678594553
x30 = -50.6581815391354
x31 = -9.8174770424681
x32 = -83.6449044018282
x33 = -3.53429173528852
x34 = -45.9457925587507
x35 = 10.2101761241668
x36 = -61.6537558266997
x37 = 0.0
x38 = -19.6349540849362
x39 = 68.329640215578
x40 = -6.67588438887831
x41 = -67.9369411338793
x42 = -121.736715326604
x43 = -30.2378292908018
x44 = -7.06858347057703
x45 = 46.7311907221482
x46 = 18.0641577581413
x47 = 30.6305283725005
x48 = -39.6626072515711
x49 = -16.1006623496477
x50 = 16.4933614313464
x51 = -41.233403578366
x52 = 60.4756585816035
x53 = 40.4480054149686
x54 = 49.872783375738
x55 = 79.717913584841
x56 = -38.484510006475
x57 = 3.92699081698724
x58 = 70.2931356240716
x59 = 5.89048622548086
x60 = 73.0420291959627
x61 = 20.0276531666349
x62 = -53.7997741927252
x63 = -27.4889357189107
x64 = 56.1559686829176
x65 = -97.7820713429823
x66 = -60.0829594999048
x67 = -1.96349540849362
x68 = 100.138265833175
x69 = 37.3064127613788
x70 = -23.9546439836222
x71 = -94.6404786893925
x72 = -71.4712328691678
x73 = 86.0010988920206
x74 = 78.1471172580461
x75 = -65.1880475619882
x76 = 66.7588438887831
x77 = 57.7267650097125
x78 = 12.1736715326604
x79 = -17.6714586764426
x80 = 93.8550805259951
x81 = -89.9280897090078
x82 = 62.0464549083984
x83 = -82.0741080750334
x84 = -74.2201264410589
x85 = -33.7721210260903
x86 = 35.7356164345839
x87 = 87.5718952188155
x88 = -38.0918109247762
x89 = -85.2157007286231
x90 = 24.3473430653209
x91 = -96.2112750161874
x92 = -8.24668071567321
x93 = 48.3019870489431
x94 = 26.3108384738145
x95 = -82.4668071567321
x95 = -82.4668071567321