Mister Exam

sin(t)<-2:3 inequation

A inequation with variable

The solution

You have entered [src]
sin(t) < -2/3
$$\sin{\left(t \right)} < - \frac{2}{3}$$
sin(t) < -2/3
Detail solution
Given the inequality:
$$\sin{\left(t \right)} < - \frac{2}{3}$$
To solve this inequality, we must first solve the corresponding equation:
$$\sin{\left(t \right)} = - \frac{2}{3}$$
Solve:
Given the equation
$$\sin{\left(t \right)} = - \frac{2}{3}$$
transform
$$\sin{\left(t \right)} + \frac{2}{3} = 0$$
$$\sin{\left(t \right)} + \frac{2}{3} = 0$$
Do replacement
$$w = \sin{\left(t \right)}$$
Move free summands (without w)
from left part to right part, we given:
$$w = - \frac{2}{3}$$
We get the answer: w = -2/3
do backward replacement
$$\sin{\left(t \right)} = w$$
substitute w:
$$x_{1} = 412.27836527649$$
$$x_{2} = 10.1545056169963$$
$$x_{3} = 93.5180519514668$$
$$x_{4} = 1216.52608459548$$
$$x_{5} = -32.1456541921249$$
$$x_{6} = -65.2437180691587$$
$$x_{7} = 30.686198879671$$
$$x_{8} = -107.54387787828$$
$$x_{9} = -302.322622400847$$
$$x_{10} = -77.8100886835179$$
$$x_{11} = -8.69505030454241$$
$$x_{12} = -38.4288394993045$$
$$x_{13} = 5.55345765095262$$
$$x_{14} = 16.4376909241759$$
$$x_{15} = -88.6943219567412$$
$$x_{16} = 18.1198282653118$$
$$x_{17} = -50.9952101136637$$
$$x_{18} = -57.2783954208432$$
$$x_{19} = 24.4030135724914$$
$$x_{20} = 55.8189401083893$$
$$x_{21} = -14.978235611722$$
$$x_{22} = 85.5527293031514$$
$$x_{23} = 72.9863586887922$$
$$x_{24} = -69.8447660352024$$
$$x_{25} = 11.8366429581322$$
$$x_{26} = 74.6684960299281$$
$$x_{27} = -33.8277915332608$$
$$x_{28} = -101.2606925711$$
$$x_{29} = -7.01291296340655$$
$$x_{30} = -0.729727656226966$$
$$x_{31} = -63.5615807280228$$
$$x_{32} = -84.0932739906975$$
$$x_{33} = 68.3853107227485$$
$$x_{34} = 60.419988074433$$
$$x_{35} = 99.8012372586464$$
$$x_{36} = -13.2960982705861$$
$$x_{37} = -58.9605327619791$$
$$x_{38} = -21.2614209189016$$
$$x_{39} = 29.0040615385351$$
$$x_{40} = 87.2348666442873$$
$$x_{41} = -2.41186499736283$$
$$x_{42} = 62.1021254155689$$
$$x_{43} = -27.5446062260812$$
$$x_{44} = -44.7120248064841$$
$$x_{45} = -94.9775072639208$$
$$x_{46} = 54.1368027672534$$
$$x_{47} = -25.8624688849453$$
$$x_{48} = 98.1190999175106$$
$$x_{49} = -836.393373511112$$
$$x_{50} = 3.87132030981676$$
$$x_{51} = -46.3941621476199$$
$$x_{52} = 22.7208762313555$$
$$x_{53} = 36.9693841868506$$
$$x_{54} = -90.376459297877$$
$$x_{55} = 175.199460944801$$
$$x_{56} = -82.4111366495616$$
$$x_{57} = 91.835914610331$$
$$x_{58} = -1755.42056570047$$
$$x_{59} = -19.5792835777657$$
$$x_{60} = 79.2695439959718$$
$$x_{61} = 49.5357548012097$$
$$x_{62} = 66.7031733816126$$
$$x_{63} = 80.9516813371077$$
$$x_{64} = -40.1109768404403$$
$$x_{65} = 47.8536174600739$$
$$x_{66} = -96.6596446050566$$
$$x_{67} = 43.2525694940301$$
$$x_{68} = -1979.9330994178$$
$$x_{69} = -71.5269033763383$$
$$x_{70} = 41.5704321528943$$
$$x_{71} = -52.6773474547995$$
$$x_{72} = 35.2872468457147$$
$$x_{73} = -76.127951342382$$
$$x_{1} = 412.27836527649$$
$$x_{2} = 10.1545056169963$$
$$x_{3} = 93.5180519514668$$
$$x_{4} = 1216.52608459548$$
$$x_{5} = -32.1456541921249$$
$$x_{6} = -65.2437180691587$$
$$x_{7} = 30.686198879671$$
$$x_{8} = -107.54387787828$$
$$x_{9} = -302.322622400847$$
$$x_{10} = -77.8100886835179$$
$$x_{11} = -8.69505030454241$$
$$x_{12} = -38.4288394993045$$
$$x_{13} = 5.55345765095262$$
$$x_{14} = 16.4376909241759$$
$$x_{15} = -88.6943219567412$$
$$x_{16} = 18.1198282653118$$
$$x_{17} = -50.9952101136637$$
$$x_{18} = -57.2783954208432$$
$$x_{19} = 24.4030135724914$$
$$x_{20} = 55.8189401083893$$
$$x_{21} = -14.978235611722$$
$$x_{22} = 85.5527293031514$$
$$x_{23} = 72.9863586887922$$
$$x_{24} = -69.8447660352024$$
$$x_{25} = 11.8366429581322$$
$$x_{26} = 74.6684960299281$$
$$x_{27} = -33.8277915332608$$
$$x_{28} = -101.2606925711$$
$$x_{29} = -7.01291296340655$$
$$x_{30} = -0.729727656226966$$
$$x_{31} = -63.5615807280228$$
$$x_{32} = -84.0932739906975$$
$$x_{33} = 68.3853107227485$$
$$x_{34} = 60.419988074433$$
$$x_{35} = 99.8012372586464$$
$$x_{36} = -13.2960982705861$$
$$x_{37} = -58.9605327619791$$
$$x_{38} = -21.2614209189016$$
$$x_{39} = 29.0040615385351$$
$$x_{40} = 87.2348666442873$$
$$x_{41} = -2.41186499736283$$
$$x_{42} = 62.1021254155689$$
$$x_{43} = -27.5446062260812$$
$$x_{44} = -44.7120248064841$$
$$x_{45} = -94.9775072639208$$
$$x_{46} = 54.1368027672534$$
$$x_{47} = -25.8624688849453$$
$$x_{48} = 98.1190999175106$$
$$x_{49} = -836.393373511112$$
$$x_{50} = 3.87132030981676$$
$$x_{51} = -46.3941621476199$$
$$x_{52} = 22.7208762313555$$
$$x_{53} = 36.9693841868506$$
$$x_{54} = -90.376459297877$$
$$x_{55} = 175.199460944801$$
$$x_{56} = -82.4111366495616$$
$$x_{57} = 91.835914610331$$
$$x_{58} = -1755.42056570047$$
$$x_{59} = -19.5792835777657$$
$$x_{60} = 79.2695439959718$$
$$x_{61} = 49.5357548012097$$
$$x_{62} = 66.7031733816126$$
$$x_{63} = 80.9516813371077$$
$$x_{64} = -40.1109768404403$$
$$x_{65} = 47.8536174600739$$
$$x_{66} = -96.6596446050566$$
$$x_{67} = 43.2525694940301$$
$$x_{68} = -1979.9330994178$$
$$x_{69} = -71.5269033763383$$
$$x_{70} = 41.5704321528943$$
$$x_{71} = -52.6773474547995$$
$$x_{72} = 35.2872468457147$$
$$x_{73} = -76.127951342382$$
This roots
$$x_{68} = -1979.9330994178$$
$$x_{58} = -1755.42056570047$$
$$x_{49} = -836.393373511112$$
$$x_{9} = -302.322622400847$$
$$x_{8} = -107.54387787828$$
$$x_{28} = -101.2606925711$$
$$x_{66} = -96.6596446050566$$
$$x_{45} = -94.9775072639208$$
$$x_{54} = -90.376459297877$$
$$x_{15} = -88.6943219567412$$
$$x_{32} = -84.0932739906975$$
$$x_{56} = -82.4111366495616$$
$$x_{10} = -77.8100886835179$$
$$x_{73} = -76.127951342382$$
$$x_{69} = -71.5269033763383$$
$$x_{24} = -69.8447660352024$$
$$x_{6} = -65.2437180691587$$
$$x_{31} = -63.5615807280228$$
$$x_{37} = -58.9605327619791$$
$$x_{18} = -57.2783954208432$$
$$x_{71} = -52.6773474547995$$
$$x_{17} = -50.9952101136637$$
$$x_{51} = -46.3941621476199$$
$$x_{44} = -44.7120248064841$$
$$x_{64} = -40.1109768404403$$
$$x_{12} = -38.4288394993045$$
$$x_{27} = -33.8277915332608$$
$$x_{5} = -32.1456541921249$$
$$x_{43} = -27.5446062260812$$
$$x_{47} = -25.8624688849453$$
$$x_{38} = -21.2614209189016$$
$$x_{59} = -19.5792835777657$$
$$x_{21} = -14.978235611722$$
$$x_{36} = -13.2960982705861$$
$$x_{11} = -8.69505030454241$$
$$x_{29} = -7.01291296340655$$
$$x_{41} = -2.41186499736283$$
$$x_{30} = -0.729727656226966$$
$$x_{50} = 3.87132030981676$$
$$x_{13} = 5.55345765095262$$
$$x_{2} = 10.1545056169963$$
$$x_{25} = 11.8366429581322$$
$$x_{14} = 16.4376909241759$$
$$x_{16} = 18.1198282653118$$
$$x_{52} = 22.7208762313555$$
$$x_{19} = 24.4030135724914$$
$$x_{39} = 29.0040615385351$$
$$x_{7} = 30.686198879671$$
$$x_{72} = 35.2872468457147$$
$$x_{53} = 36.9693841868506$$
$$x_{70} = 41.5704321528943$$
$$x_{67} = 43.2525694940301$$
$$x_{65} = 47.8536174600739$$
$$x_{61} = 49.5357548012097$$
$$x_{46} = 54.1368027672534$$
$$x_{20} = 55.8189401083893$$
$$x_{34} = 60.419988074433$$
$$x_{42} = 62.1021254155689$$
$$x_{62} = 66.7031733816126$$
$$x_{33} = 68.3853107227485$$
$$x_{23} = 72.9863586887922$$
$$x_{26} = 74.6684960299281$$
$$x_{60} = 79.2695439959718$$
$$x_{63} = 80.9516813371077$$
$$x_{22} = 85.5527293031514$$
$$x_{40} = 87.2348666442873$$
$$x_{57} = 91.835914610331$$
$$x_{3} = 93.5180519514668$$
$$x_{48} = 98.1190999175106$$
$$x_{35} = 99.8012372586464$$
$$x_{55} = 175.199460944801$$
$$x_{1} = 412.27836527649$$
$$x_{4} = 1216.52608459548$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{68}$$
For example, let's take the point
$$x_{0} = x_{68} - \frac{1}{10}$$
=
$$-1979.9330994178 + - \frac{1}{10}$$
=
$$-1980.0330994178$$
substitute to the expression
$$\sin{\left(t \right)} < - \frac{2}{3}$$
$$\sin{\left(t \right)} < - \frac{2}{3}$$
sin(t) < -2/3

Then
$$x < -1979.9330994178$$
no execute
one of the solutions of our inequality is:
$$x > -1979.9330994178 \wedge x < -1755.42056570047$$
         _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____  
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-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------
       x68      x58      x49      x9      x8      x28      x66      x45      x54      x15      x32      x56      x10      x73      x69      x24      x6      x31      x37      x18      x71      x17      x51      x44      x64      x12      x27      x5      x43      x47      x38      x59      x21      x36      x11      x29      x41      x30      x50      x13      x2      x25      x14      x16      x52      x19      x39      x7      x72      x53      x70      x67      x65      x61      x46      x20      x34      x42      x62      x33      x23      x26      x60      x63      x22      x40      x57      x3      x48      x35      x55      x1      x4

Other solutions will get with the changeover to the next point
etc.
The answer:
$$x > -1979.9330994178 \wedge x < -1755.42056570047$$
$$x > -836.393373511112 \wedge x < -302.322622400847$$
$$x > -107.54387787828 \wedge x < -101.2606925711$$
$$x > -96.6596446050566 \wedge x < -94.9775072639208$$
$$x > -90.376459297877 \wedge x < -88.6943219567412$$
$$x > -84.0932739906975 \wedge x < -82.4111366495616$$
$$x > -77.8100886835179 \wedge x < -76.127951342382$$
$$x > -71.5269033763383 \wedge x < -69.8447660352024$$
$$x > -65.2437180691587 \wedge x < -63.5615807280228$$
$$x > -58.9605327619791 \wedge x < -57.2783954208432$$
$$x > -52.6773474547995 \wedge x < -50.9952101136637$$
$$x > -46.3941621476199 \wedge x < -44.7120248064841$$
$$x > -40.1109768404403 \wedge x < -38.4288394993045$$
$$x > -33.8277915332608 \wedge x < -32.1456541921249$$
$$x > -27.5446062260812 \wedge x < -25.8624688849453$$
$$x > -21.2614209189016 \wedge x < -19.5792835777657$$
$$x > -14.978235611722 \wedge x < -13.2960982705861$$
$$x > -8.69505030454241 \wedge x < -7.01291296340655$$
$$x > -2.41186499736283 \wedge x < -0.729727656226966$$
$$x > 3.87132030981676 \wedge x < 5.55345765095262$$
$$x > 10.1545056169963 \wedge x < 11.8366429581322$$
$$x > 16.4376909241759 \wedge x < 18.1198282653118$$
$$x > 22.7208762313555 \wedge x < 24.4030135724914$$
$$x > 29.0040615385351 \wedge x < 30.686198879671$$
$$x > 35.2872468457147 \wedge x < 36.9693841868506$$
$$x > 41.5704321528943 \wedge x < 43.2525694940301$$
$$x > 47.8536174600739 \wedge x < 49.5357548012097$$
$$x > 54.1368027672534 \wedge x < 55.8189401083893$$
$$x > 60.419988074433 \wedge x < 62.1021254155689$$
$$x > 66.7031733816126 \wedge x < 68.3853107227485$$
$$x > 72.9863586887922 \wedge x < 74.6684960299281$$
$$x > 79.2695439959718 \wedge x < 80.9516813371077$$
$$x > 85.5527293031514 \wedge x < 87.2348666442873$$
$$x > 91.835914610331 \wedge x < 93.5180519514668$$
$$x > 98.1190999175106 \wedge x < 99.8012372586464$$
$$x > 175.199460944801 \wedge x < 412.27836527649$$
$$x > 1216.52608459548$$
Rapid solution [src]
   /          /    ___\                  /    ___\    \
   |          |2*\/ 5 |                  |2*\/ 5 |    |
And|t < - atan|-------| + 2*pi, pi + atan|-------| < t|
   \          \   5   /                  \   5   /    /
$$t < - \operatorname{atan}{\left(\frac{2 \sqrt{5}}{5} \right)} + 2 \pi \wedge \operatorname{atan}{\left(\frac{2 \sqrt{5}}{5} \right)} + \pi < t$$
(pi + atan(2*sqrt(5)/5) < t)∧(t < -atan(2*sqrt(5)/5) + 2*pi)
Rapid solution 2 [src]
          /    ___\        /    ___\        
          |2*\/ 5 |        |2*\/ 5 |        
(pi + atan|-------|, - atan|-------| + 2*pi)
          \   5   /        \   5   /        
$$x\ in\ \left(\operatorname{atan}{\left(\frac{2 \sqrt{5}}{5} \right)} + \pi, - \operatorname{atan}{\left(\frac{2 \sqrt{5}}{5} \right)} + 2 \pi\right)$$
x in Interval.open(atan(2*sqrt(5)/5) + pi, -atan(2*sqrt(5)/5) + 2*pi)