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|sin(x)|cos(x)>1/4 inequation

A inequation with variable

The solution

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|sin(x)|*cos(x) > 1/4
$$\cos{\left(x \right)} \left|{\sin{\left(x \right)}}\right| > \frac{1}{4}$$
cos(x)*Abs(sin(x)) > 1/4
Detail solution
Given the inequality:
$$\cos{\left(x \right)} \left|{\sin{\left(x \right)}}\right| > \frac{1}{4}$$
To solve this inequality, we must first solve the corresponding equation:
$$\cos{\left(x \right)} \left|{\sin{\left(x \right)}}\right| = \frac{1}{4}$$
Solve:
$$x_{1} = -13.8753675533549$$
$$x_{2} = 56.2868683768171$$
$$x_{3} = -50.0036830696375$$
$$x_{4} = 93.9859802198946$$
$$x_{5} = 80.3724120543389$$
$$x_{6} = 36.3901149040818$$
$$x_{7} = 57.857664703612$$
$$x_{8} = -3707.34113062376$$
$$x_{9} = 7.59218224617533$$
$$x_{10} = -55.2396708256205$$
$$x_{11} = -82.9904059323304$$
$$x_{12} = -30.1069295969022$$
$$x_{13} = -95.5567765466895$$
$$x_{14} = -74.0892267471593$$
$$x_{15} = 12.30457122656$$
$$x_{16} = -43.720497762458$$
$$x_{17} = 45.2912940892529$$
$$x_{18} = 6.54498469497874$$
$$x_{19} = -12.8281700021583$$
$$x_{20} = -51.5744793964324$$
$$x_{21} = -231.168859426649$$
$$x_{22} = -70.4240353179712$$
$$x_{23} = -17.540558982543$$
$$x_{24} = -61.5228561328001$$
$$x_{25} = 100.269165527074$$
$$x_{26} = -0.261799387799149$$
$$x_{27} = -12.30457122656$$
$$x_{28} = -6.02138591938044$$
$$x_{29} = 51.5744793964324$$
$$x_{30} = -19.1113553093379$$
$$x_{31} = 95.5567765466895$$
$$x_{32} = -20.1585528605345$$
$$x_{33} = -80.3724120543389$$
$$x_{34} = 20.1585528605345$$
$$x_{35} = 50.0036830696375$$
$$x_{36} = 70.4240353179712$$
$$x_{37} = 67.8060414399797$$
$$x_{38} = 107.075949609852$$
$$x_{39} = -36.3901149040818$$
$$x_{40} = -68.8532389911763$$
$$x_{41} = -50.5272818452358$$
$$x_{42} = -1368.42540002615$$
$$x_{43} = 0.261799387799149$$
$$x_{44} = -42.6733002112614$$
$$x_{45} = -75.6600230739542$$
$$x_{46} = -86.6555973615185$$
$$x_{47} = 86.6555973615185$$
$$x_{48} = -87.7027949127151$$
$$x_{49} = -37.9609112308767$$
$$x_{50} = 64.1408500107916$$
$$x_{51} = -67.8060414399797$$
$$x_{52} = -1.30899693899575$$
$$x_{53} = -100.792764302673$$
$$x_{54} = 76.7072206251508$$
$$x_{55} = 26.4417381677141$$
$$x_{56} = -37.4373124552784$$
$$x_{57} = 23.8237442897226$$
$$x_{58} = -93.9859802198946$$
$$x_{59} = -31.6777259236971$$
$$x_{60} = 30.1069295969022$$
$$x_{61} = 81.9432083811338$$
$$x_{62} = 6.02138591938044$$
$$x_{63} = -7.59218224617533$$
$$x_{64} = -81.4196096055355$$
$$x_{65} = -25.3945406165175$$
$$x_{66} = -81.9432083811338$$
$$x_{67} = 55.2396708256205$$
$$x_{68} = 74.0892267471593$$
$$x_{69} = 37.9609112308767$$
$$x_{70} = 48.9564855184409$$
$$x_{71} = 88.2263936883134$$
$$x_{72} = -89.27359123951$$
$$x_{73} = 44.2440965380563$$
$$x_{74} = 114.406332468228$$
$$x_{75} = -64.1408500107916$$
$$x_{76} = -23.8237442897226$$
$$x_{77} = 13.8753675533549$$
$$x_{78} = -56.8104671524154$$
$$x_{79} = -45.2912940892529$$
$$x_{80} = -57.857664703612$$
$$x_{81} = 31.1541271480988$$
$$x_{82} = 42.6733002112614$$
$$x_{1} = -13.8753675533549$$
$$x_{2} = 56.2868683768171$$
$$x_{3} = -50.0036830696375$$
$$x_{4} = 93.9859802198946$$
$$x_{5} = 80.3724120543389$$
$$x_{6} = 36.3901149040818$$
$$x_{7} = 57.857664703612$$
$$x_{8} = -3707.34113062376$$
$$x_{9} = 7.59218224617533$$
$$x_{10} = -55.2396708256205$$
$$x_{11} = -82.9904059323304$$
$$x_{12} = -30.1069295969022$$
$$x_{13} = -95.5567765466895$$
$$x_{14} = -74.0892267471593$$
$$x_{15} = 12.30457122656$$
$$x_{16} = -43.720497762458$$
$$x_{17} = 45.2912940892529$$
$$x_{18} = 6.54498469497874$$
$$x_{19} = -12.8281700021583$$
$$x_{20} = -51.5744793964324$$
$$x_{21} = -231.168859426649$$
$$x_{22} = -70.4240353179712$$
$$x_{23} = -17.540558982543$$
$$x_{24} = -61.5228561328001$$
$$x_{25} = 100.269165527074$$
$$x_{26} = -0.261799387799149$$
$$x_{27} = -12.30457122656$$
$$x_{28} = -6.02138591938044$$
$$x_{29} = 51.5744793964324$$
$$x_{30} = -19.1113553093379$$
$$x_{31} = 95.5567765466895$$
$$x_{32} = -20.1585528605345$$
$$x_{33} = -80.3724120543389$$
$$x_{34} = 20.1585528605345$$
$$x_{35} = 50.0036830696375$$
$$x_{36} = 70.4240353179712$$
$$x_{37} = 67.8060414399797$$
$$x_{38} = 107.075949609852$$
$$x_{39} = -36.3901149040818$$
$$x_{40} = -68.8532389911763$$
$$x_{41} = -50.5272818452358$$
$$x_{42} = -1368.42540002615$$
$$x_{43} = 0.261799387799149$$
$$x_{44} = -42.6733002112614$$
$$x_{45} = -75.6600230739542$$
$$x_{46} = -86.6555973615185$$
$$x_{47} = 86.6555973615185$$
$$x_{48} = -87.7027949127151$$
$$x_{49} = -37.9609112308767$$
$$x_{50} = 64.1408500107916$$
$$x_{51} = -67.8060414399797$$
$$x_{52} = -1.30899693899575$$
$$x_{53} = -100.792764302673$$
$$x_{54} = 76.7072206251508$$
$$x_{55} = 26.4417381677141$$
$$x_{56} = -37.4373124552784$$
$$x_{57} = 23.8237442897226$$
$$x_{58} = -93.9859802198946$$
$$x_{59} = -31.6777259236971$$
$$x_{60} = 30.1069295969022$$
$$x_{61} = 81.9432083811338$$
$$x_{62} = 6.02138591938044$$
$$x_{63} = -7.59218224617533$$
$$x_{64} = -81.4196096055355$$
$$x_{65} = -25.3945406165175$$
$$x_{66} = -81.9432083811338$$
$$x_{67} = 55.2396708256205$$
$$x_{68} = 74.0892267471593$$
$$x_{69} = 37.9609112308767$$
$$x_{70} = 48.9564855184409$$
$$x_{71} = 88.2263936883134$$
$$x_{72} = -89.27359123951$$
$$x_{73} = 44.2440965380563$$
$$x_{74} = 114.406332468228$$
$$x_{75} = -64.1408500107916$$
$$x_{76} = -23.8237442897226$$
$$x_{77} = 13.8753675533549$$
$$x_{78} = -56.8104671524154$$
$$x_{79} = -45.2912940892529$$
$$x_{80} = -57.857664703612$$
$$x_{81} = 31.1541271480988$$
$$x_{82} = 42.6733002112614$$
This roots
$$x_{8} = -3707.34113062376$$
$$x_{42} = -1368.42540002615$$
$$x_{21} = -231.168859426649$$
$$x_{53} = -100.792764302673$$
$$x_{13} = -95.5567765466895$$
$$x_{58} = -93.9859802198946$$
$$x_{72} = -89.27359123951$$
$$x_{48} = -87.7027949127151$$
$$x_{46} = -86.6555973615185$$
$$x_{11} = -82.9904059323304$$
$$x_{66} = -81.9432083811338$$
$$x_{64} = -81.4196096055355$$
$$x_{33} = -80.3724120543389$$
$$x_{45} = -75.6600230739542$$
$$x_{14} = -74.0892267471593$$
$$x_{22} = -70.4240353179712$$
$$x_{40} = -68.8532389911763$$
$$x_{51} = -67.8060414399797$$
$$x_{75} = -64.1408500107916$$
$$x_{24} = -61.5228561328001$$
$$x_{80} = -57.857664703612$$
$$x_{78} = -56.8104671524154$$
$$x_{10} = -55.2396708256205$$
$$x_{20} = -51.5744793964324$$
$$x_{41} = -50.5272818452358$$
$$x_{3} = -50.0036830696375$$
$$x_{79} = -45.2912940892529$$
$$x_{16} = -43.720497762458$$
$$x_{44} = -42.6733002112614$$
$$x_{49} = -37.9609112308767$$
$$x_{56} = -37.4373124552784$$
$$x_{39} = -36.3901149040818$$
$$x_{59} = -31.6777259236971$$
$$x_{12} = -30.1069295969022$$
$$x_{65} = -25.3945406165175$$
$$x_{76} = -23.8237442897226$$
$$x_{32} = -20.1585528605345$$
$$x_{30} = -19.1113553093379$$
$$x_{23} = -17.540558982543$$
$$x_{1} = -13.8753675533549$$
$$x_{19} = -12.8281700021583$$
$$x_{27} = -12.30457122656$$
$$x_{63} = -7.59218224617533$$
$$x_{28} = -6.02138591938044$$
$$x_{52} = -1.30899693899575$$
$$x_{26} = -0.261799387799149$$
$$x_{43} = 0.261799387799149$$
$$x_{62} = 6.02138591938044$$
$$x_{18} = 6.54498469497874$$
$$x_{9} = 7.59218224617533$$
$$x_{15} = 12.30457122656$$
$$x_{77} = 13.8753675533549$$
$$x_{34} = 20.1585528605345$$
$$x_{57} = 23.8237442897226$$
$$x_{55} = 26.4417381677141$$
$$x_{60} = 30.1069295969022$$
$$x_{81} = 31.1541271480988$$
$$x_{6} = 36.3901149040818$$
$$x_{69} = 37.9609112308767$$
$$x_{82} = 42.6733002112614$$
$$x_{73} = 44.2440965380563$$
$$x_{17} = 45.2912940892529$$
$$x_{70} = 48.9564855184409$$
$$x_{35} = 50.0036830696375$$
$$x_{29} = 51.5744793964324$$
$$x_{67} = 55.2396708256205$$
$$x_{2} = 56.2868683768171$$
$$x_{7} = 57.857664703612$$
$$x_{50} = 64.1408500107916$$
$$x_{37} = 67.8060414399797$$
$$x_{36} = 70.4240353179712$$
$$x_{68} = 74.0892267471593$$
$$x_{54} = 76.7072206251508$$
$$x_{5} = 80.3724120543389$$
$$x_{61} = 81.9432083811338$$
$$x_{47} = 86.6555973615185$$
$$x_{71} = 88.2263936883134$$
$$x_{4} = 93.9859802198946$$
$$x_{31} = 95.5567765466895$$
$$x_{25} = 100.269165527074$$
$$x_{38} = 107.075949609852$$
$$x_{74} = 114.406332468228$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{8}$$
For example, let's take the point
$$x_{0} = x_{8} - \frac{1}{10}$$
=
$$-3707.34113062376 + - \frac{1}{10}$$
=
$$-3707.44113062376$$
substitute to the expression
$$\cos{\left(x \right)} \left|{\sin{\left(x \right)}}\right| > \frac{1}{4}$$
$$\cos{\left(-3707.44113062376 \right)} \left|{\sin{\left(-3707.44113062376 \right)}}\right| > \frac{1}{4}$$
0.331042988171074 > 1/4

one of the solutions of our inequality is:
$$x < -3707.34113062376$$
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       x8      x42      x21      x53      x13      x58      x72      x48      x46      x11      x66      x64      x33      x45      x14      x22      x40      x51      x75      x24      x80      x78      x10      x20      x41      x3      x79      x16      x44      x49      x56      x39      x59      x12      x65      x76      x32      x30      x23      x1      x19      x27      x63      x28      x52      x26      x43      x62      x18      x9      x15      x77      x34      x57      x55      x60      x81      x6      x69      x82      x73      x17      x70      x35      x29      x67      x2      x7      x50      x37      x36      x68      x54      x5      x61      x47      x71      x4      x31      x25      x38      x74

Other solutions will get with the changeover to the next point
etc.
The answer:
$$x < -3707.34113062376$$
$$x > -1368.42540002615 \wedge x < -231.168859426649$$
$$x > -100.792764302673 \wedge x < -95.5567765466895$$
$$x > -93.9859802198946 \wedge x < -89.27359123951$$
$$x > -87.7027949127151 \wedge x < -86.6555973615185$$
$$x > -82.9904059323304 \wedge x < -81.9432083811338$$
$$x > -81.4196096055355 \wedge x < -80.3724120543389$$
$$x > -75.6600230739542 \wedge x < -74.0892267471593$$
$$x > -70.4240353179712 \wedge x < -68.8532389911763$$
$$x > -67.8060414399797 \wedge x < -64.1408500107916$$
$$x > -61.5228561328001 \wedge x < -57.857664703612$$
$$x > -56.8104671524154 \wedge x < -55.2396708256205$$
$$x > -51.5744793964324 \wedge x < -50.5272818452358$$
$$x > -50.0036830696375 \wedge x < -45.2912940892529$$
$$x > -43.720497762458 \wedge x < -42.6733002112614$$
$$x > -37.9609112308767 \wedge x < -37.4373124552784$$
$$x > -36.3901149040818 \wedge x < -31.6777259236971$$
$$x > -30.1069295969022 \wedge x < -25.3945406165175$$
$$x > -23.8237442897226 \wedge x < -20.1585528605345$$
$$x > -19.1113553093379 \wedge x < -17.540558982543$$
$$x > -13.8753675533549 \wedge x < -12.8281700021583$$
$$x > -12.30457122656 \wedge x < -7.59218224617533$$
$$x > -6.02138591938044 \wedge x < -1.30899693899575$$
$$x > -0.261799387799149 \wedge x < 0.261799387799149$$
$$x > 6.02138591938044 \wedge x < 6.54498469497874$$
$$x > 7.59218224617533 \wedge x < 12.30457122656$$
$$x > 13.8753675533549 \wedge x < 20.1585528605345$$
$$x > 23.8237442897226 \wedge x < 26.4417381677141$$
$$x > 30.1069295969022 \wedge x < 31.1541271480988$$
$$x > 36.3901149040818 \wedge x < 37.9609112308767$$
$$x > 42.6733002112614 \wedge x < 44.2440965380563$$
$$x > 45.2912940892529 \wedge x < 48.9564855184409$$
$$x > 50.0036830696375 \wedge x < 51.5744793964324$$
$$x > 55.2396708256205 \wedge x < 56.2868683768171$$
$$x > 57.857664703612 \wedge x < 64.1408500107916$$
$$x > 67.8060414399797 \wedge x < 70.4240353179712$$
$$x > 74.0892267471593 \wedge x < 76.7072206251508$$
$$x > 80.3724120543389 \wedge x < 81.9432083811338$$
$$x > 86.6555973615185 \wedge x < 88.2263936883134$$
$$x > 93.9859802198946 \wedge x < 95.5567765466895$$
$$x > 100.269165527074 \wedge x < 107.075949609852$$
$$x > 114.406332468228$$
Solving inequality on a graph