Modulus inequality some different concepts
Consider, ![|x + 1| - |x| < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uOIR0z3ZejIJM35VhoQvvMFHcA1pxFDzOvWZFr0ozohzimhm26Jk-2QMT1toABnm67Na8ECBS2Y6A5eZoSxy_-tJj5HM2tE-DHYbeQteHBirVgO-qMJoJKlZSIHjd0HY0dDyhNjVF3MVhxXae9K24SQGnj_0_J0UGcVpOohXq0RUxGGACaKa7wv0uSATXV_clWdbR3=s0-d)
means, we have to find those values for x for which the difference of distance from -1 and 0 is less than 2
By distance method discussed in http://iitmathseasy.blogspot.in/2013/03/modulus-equality-solving-concept-ii.html
"d" denotes distance
from figure, it is clear that if we take any value less than -1 , consider![a < - 1](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sxoXlsNjNg9HJ8oGWyWMzyS0YtQF69TsgHfAXCRpKxBLYfZYuiu--LLgtE_8-XFAeITMTGNqEQJ7zq54-FZTAzBGu2h7Vf9ukarM14ZnMhovEliZHEHq7baiEE6JsPrjpiHrEUopABK6KL9Fj9z5cXtydil6uR2qqu-pExnPKS2A8=s0-d)
( because nearer to -1 than 0)
therefore ,![d( - 1,a) - d(0,a) < 0](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uqybQUT9EQVtwcB6kjo0GVmXjEWTjwy19jJTeoPXe4IfyctEUQSvvi4g8WwrKoqMuJjf5AZxq6TbhjYKvqYjtTpzD5icVSxPVBn7OIwuoIhcN8tX7H-1m1JEwDeQqwxI-cY7FsH3y1mzvVWJfUiHboM-o4xWmaljdgf1h7-I9UzkjsgSI4iUJJ0IOGMlPKlw=s0-d)
means, for any point less than -1
![|x + 1| - |x| < 0 < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_vWtjzjoTle4DNiiTVCL8uhshv6f6EwFh4MPmAvkutXEb_p5gEikKjocvzgqsbPp6skVTCfrgL9DCJ_krC-w1erKLDkNx83Lm0aEb_5tsOvRGikPo0Njw_8DjHDBQq6nrXjA3D2RfPScQiBpWAmBa6Nok5jra3riCliO8ZB92Y5rgKoH6C6wXhG1nGHOAb0prS2zHPnzrQLk1Ra=s0-d)
e.g. take![x = - 3](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tgxoVvf2ZjsJ_JIVyb9r974c9Yfiy3Dv1WoSepQUZnRAD6cCJRatpUIDPKi1aaCSAyrwsYTy_EhpYffB13NKPWA9Qlq1Afcv2HRhc1k1WBJh2586DTiqO0t-0RWAT-mG_0sfMDH_IVAUMU4-q_rUIGHETVdiOLbM0tycmX_h8NL0A=s0-d)
( put x = -3, |x + 1| )
and,
( put x = -3 , |x| )
therefore,
( difference will always be -1, see figure )
i.e.![|x + 1| - |x| = - 1 < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_v_-InaRJobIC5uzz8Z518rXfX8bNGwafTukezkDjzItcqPuZYriT4ND3Sq7qnRlxBmp5gGhM9qxnqsRdWuVpOGAeU5_nytxWjsUI5BUX5yPQvqgiMaCwyhGL7kDEuiErS-QMnFAfN3ljI2et28KCGc1bdFCymql1wRVBXFe9naok9jZ1IcB5kk9iyvkQsdj7kFEUyafEtKlqA1_gpJ=s0-d)
therefore , for all values less than -1 inequality satisfies.
consider , any point between -1 and 0 including -1 and 0
since,
,
therefore for no points the difference between difference from -1 and 0 will exceed 2.
implies that for all values between and including -1 and 0 inequality satisfies.
i.e.![d( - 1,a) - d(0,a) \le 1 < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_vZjNth75A7vgzIklyaxIUWDd0uGf5724MQWlOvHA_71QPjD0ALxSh5JtUR5yDd4Ib_dRR6Vra7h_RX5B4yoMk33DeBbKSwD_XCyN5TfFcVvn-7KCPCVC15JGHGYfMEmX6IPIpURLZwW3wnqlI0IA5ROvZ6siP5gzkPBuUpjHq97mV2bDozniaRR6CwdeVgYx6t9D0eTzA=s0-d)
, ( -1 gives -1 and 0 gives 1, )
consider, any point greater than 0,
clearly from figure difference will always be 1
![|x + 1| - |x| = 1 < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tvMuuwdOJtQqVkrJKSwl6MWTQ0uX5szQpQiaVZn8neoAhY6wUmvAvPbKFK8cEjKyjgrfxyletIGuKE9G9SS_1Bqd-0cPUMh36l7pfx_pZEokgAiuVUq2jw-qHEm0fU6DkodOoAj7zyqD3194zziRzbbonv48DUIRGz_aMCMaTBUxdf-HgWTLFWEQH0lMFNeAcP6509-7kNlK4=s0-d)
therefore, for all values greater than 0 inequality satisfies.
considering all the statements, inequality satisfies for all Real Numbers.
![x \in ( - \infty ,\infty )](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tu55HlJflNkMb1rsDVDWrHb_BnHegmK7nLpFzC8obHjEKYhjJeN7JV30bovQUji_oQGIWsGk7bdk95wG88zl7xnogAA6SK6sKm93YeXsIixCWZZVmR7qK7a5tonpvhAA9DxVZe379vhrfn7z_VjQMykPSRu0dwsRjvqXDFKCEa38qKgBJFtolxci7iHWhFHO0sKz6V61I=s0-d)
or![x \in R](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_txoZSpWpqBhaRq6pDz6pNEJ9D2AiKbc8bS1kwOeyqeLfC0stiG5zTT51iV-TSQBr14z0brCHP6sdFvWFJblYDGEQocoBEWmd9mDNYauPg2jo_6YQOaAwUYwW64dBkWdWlB5JPSfyBjIs6EHstWiKf6xDREovKcf4x4Azf0Oyy7=s0-d)
Second method,
![|x + 1| - |x| < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uOIR0z3ZejIJM35VhoQvvMFHcA1pxFDzOvWZFr0ozohzimhm26Jk-2QMT1toABnm67Na8ECBS2Y6A5eZoSxy_-tJj5HM2tE-DHYbeQteHBirVgO-qMJoJKlZSIHjd0HY0dDyhNjVF3MVhxXae9K24SQGnj_0_J0UGcVpOohXq0RUxGGACaKa7wv0uSATXV_clWdbR3=s0-d)
from graph,
there are two curves,
and ![y = 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_s0862WpTbSJIXQ1__WCdjtxrggMAuoh3WCmKpcQ9QZ1Q8u4ka4QUequohrA2RQX2QjOnHbkT6Fg1ZrSRWx2lV8vbG-xpphfYdfPqjHy6OAGpcsHYLFZ5y4ywRHU6hYXXjB4rmpdTQmMXErplwhNyUfOR9-lhWIxz00g2sdOWM=s0-d)
and we have to find those values of x for which
is less than
i.e.
will below the line ![y = 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_s0862WpTbSJIXQ1__WCdjtxrggMAuoh3WCmKpcQ9QZ1Q8u4ka4QUequohrA2RQX2QjOnHbkT6Fg1ZrSRWx2lV8vbG-xpphfYdfPqjHy6OAGpcsHYLFZ5y4ywRHU6hYXXjB4rmpdTQmMXErplwhNyUfOR9-lhWIxz00g2sdOWM=s0-d)
consider,![y = |x + 1| - |x|](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_viG5_AkXY9XX2TIQhZ74WPgh2ZACaxE-vlz3SuT0zhXwgdI_Add5f6QJCl3o-jFRTCm8M9ZBB1oem0D7fuRjundySSH7KIBdoFtO9DdgWJMV0Ap-ncIpdhtE8aKTj9Gy1vgQZ9-AgkvubzX54YFmIzHgSSSQozhIhopj_GBfSRrZoHv-uejT7MIO3-sHa7UD-kc3E=s0-d)
two critical points -1 and 0
for,![x \le - 1](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_s02-iNTYbPhSxN7tIZUZU0NHmE2waNa9Utlpx3z8YVF9E7Uh6_tV7yaDkStc30mN5FHgKBagngyO62em2kzf9Qwklj9Jfxh-jwwO_zMmTlsdIq7m-wpwwjTAYhaFXNJ_IGp4DM4uhZgG6Bf810eo3euPbFeUh-MN-iXRKNtrvlYmKS2A=s0-d)
![y = - x - 1 - ( - x)](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tqZFnMwKE0Iw3uxDShc3Fh_WvPT0x5z415sbgPQ3j4p-au4eNHMgBvC2Xxz-jKmMUgADKvD5XvR46l0XFFCtO9xXFpZbGiYAJ0QPDR77Z31rhICmM4XtcU2GeBLXmbfArdioNnZnqgnQCujrSOF5vaulBWH3kiPgSrOMufJLPw_T0sx5SZtpRVwNMzTqcA=s0-d)
![y = - 1](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uLmv9rJuoSKoSFpJm3ugAGeUq8slMXhA8tieq-LH92dWhfNbIp1f5ssdyDe3Grt2teD5o_pavFsgXoPlEXdCnDRapxsBl6ag5rYFbKZoRx_38hLjtApD2vjyCjhGQ5YpvBGLC2Zb4SO1tkdx9exIx0-gX45MVnP1IfG33OX91w1w=s0-d)
for,![- 1 \le x \le 0](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sVN1U2UYQVVTv7fvjjWpzmpmWFZaX_d0Jn2hUbQyQsPkTrZI6_eC10Gw977CXsdmFna3kUEJaGRd82zXANUtBlLF1egq2XE70l2qyiX1oeDQyz7Nkl-ehTqgApIyLpDiMUNR4plEhj_VJKCvBewgd-bF3Mh8zBRpPALl_bvc9JyOBN3ipTC5tbDQ=s0-d)
![y = x + 1 - ( - x)](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_vvB9bgR9oYzECRPyXy1kg-dPTl9ux6lAJgwWB1VDahsQaxre7Qnfv0TWcwDHCw0_pgxHDqWaIGwl2mfVcqU7Ys37Rqi86C1F_fvLCfm2jdpcTQCCX_oc4swmosYZjt6zhDKvz1ShMipeB1thG4pFMAtl7d0yYSk9W4I5yjCvAzSycuHP2ttGFN4-3ktt4=s0-d)
,
we need two points to draw a line.
put x = -1
y = -1
and for x = 0
y = 1
for,![x \ge 0](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_syQtRiW1kC2Lg82dJLUlKmmRHzlsyiNcUlzMG-1L1Jm8Ia1ZROzME3lbx3RlkIpntQUFP4b-hLVDnVdIDBOrMa4Z97xEFrS2oWCptUDheB4TkCD0f-lFy39PQYhukrwm3TuFJR3gkr5ztVcu5r2gsr0-eqYx0yOqgOhLuzr1shEg=s0-d)
![y = x + 1 - (x)](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_su8R0Pn7jgiuV9vm2E1OIuYcCyxL7COSIGPvVvB4UMASxUVtx4Egb0NmdQchm1Ht1gae72_fSIVJoER4ki7LPgGqL9qodtzWDQe1qCZQZFwm7UrSAfCjKQ07McRhGrRXA3Be2jLqHJrhfma1UPH4O18F3Pbf4xMzudUdX5tOJ3vy9ttTj5SmSeFA=s0-d)
![y = 1](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uJyM1E884Og4NLBlMVTNTp3YczCsG7oIcPBcsvvVFimmvhbpw03zBHszJILBkWeoZHK7tWeufJDGaFWC359zK0BYw22FO5w_thyHdQxZUUFBo3FRrf10ycufs0Xv7fOmJyo8l1FyfXIBuX-GS5vdJlPNskc_O2-PfeVq28ols=s0-d)
plot the graph as mentioned above,
as cleared from the above graph,
is always less than or below to
,
therefore for
, ![|x + 1| - |x| < 2](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uOIR0z3ZejIJM35VhoQvvMFHcA1pxFDzOvWZFr0ozohzimhm26Jk-2QMT1toABnm67Na8ECBS2Y6A5eZoSxy_-tJj5HM2tE-DHYbeQteHBirVgO-qMJoJKlZSIHjd0HY0dDyhNjVF3MVhxXae9K24SQGnj_0_J0UGcVpOohXq0RUxGGACaKa7wv0uSATXV_clWdbR3=s0-d)
means, we have to find those values for x for which the difference of distance from -1 and 0 is less than 2
By distance method discussed in http://iitmathseasy.blogspot.in/2013/03/modulus-equality-solving-concept-ii.html
"d" denotes distance
from figure, it is clear that if we take any value less than -1 , consider
therefore ,
means, for any point less than -1
e.g. take
and,
therefore,
i.e.
therefore , for all values less than -1 inequality satisfies.
consider , any point between -1 and 0 including -1 and 0
since,
therefore for no points the difference between difference from -1 and 0 will exceed 2.
implies that for all values between and including -1 and 0 inequality satisfies.
i.e.
consider, any point greater than 0,
clearly from figure difference will always be 1
therefore, for all values greater than 0 inequality satisfies.
considering all the statements, inequality satisfies for all Real Numbers.
or
Second method,
from graph,
there are two curves,
and we have to find those values of x for which
consider,
two critical points -1 and 0
for,
for,
we need two points to draw a line.
put x = -1
y = -1
and for x = 0
y = 1
for,
plot the graph as mentioned above,
as cleared from the above graph,
therefore for
very good work. very helpful indeed.
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