{"id":89992,"date":"2025-06-01T10:18:43","date_gmt":"2025-06-01T10:18:43","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=89992"},"modified":"2025-06-01T10:18:43","modified_gmt":"2025-06-01T10:18:43","slug":"which-one-of-the-following-inequalities-is-always-true-for-positive-re","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/","title":{"rendered":"Which one of the following inequalities is always true for positive re"},"content":{"rendered":"<p>Which one of the following inequalities is always true for positive real numbers x, y ?<\/p>\n<p>[amp_mcq option1=&#8221;xy > x + y&#8221; option2=&#8221;(x + y) < (x + y)\u00b2\" option3=\"x + y < x\u00b2 + y\u00b2\" option4=\"1 + x + y < (1 + x + y)\u00b2\" correct=\"option4\"]\n\n\n\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC CAPF &#8211; 2016<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-capf-2016.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-capf-2016\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe correct answer is D) 1 + x + y < (1 + x + y)\u00b2.\n<\/section>\n<section id=\"pyq-key-points\">\n&#8211; The question asks for the inequality that is *always* true for positive real numbers x and y.<br \/>\n&#8211; A) xy > x + y: If x=1, y=1, 1 > 2 is false. Not always true.<br \/>\n&#8211; B) (x + y) < (x + y)\u00b2: Let z = x + y. Since x, y > 0, z > 0. The inequality is z < z\u00b2. This is equivalent to z\u00b2 - z > 0, or z(z-1) > 0. Since z > 0, this is true only if z-1 > 0, i.e., z > 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 < (0.2)\u00b2 = 0.04 is false. Not always true.\n- C) x + y < x\u00b2 + y\u00b2: If x=1, y=1, 1+1 < 1\u00b2+1\u00b2 is 2 < 2, which is false. If x=0.5, y=0.5, 0.5+0.5 < 0.5\u00b2+0.5\u00b2 is 1 < 0.25+0.25=0.5, which is false. Not always true.\n- D) 1 + x + y < (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x>0, y>0), 1 + x + y must be greater than 1 (w > 1). The inequality becomes w < w\u00b2. This is equivalent to w\u00b2 - w > 0, or w(w-1) > 0. Since w > 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w < w\u00b2 is always true when w > 1. As 1 + x + y > 1 for positive x, y, the inequality 1 + x + y < (1 + x + y)\u00b2 is always true.\n<\/section>\n<section id=\"pyq-additional-information\">\nThe inequality z < z\u00b2 is true for z < 0 or z > 1. Since x, y are positive, 1 + x + y is always greater than 1, falling into the w > 1 range.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Which one of the following inequalities is always true for positive real numbers x, y ? [amp_mcq option1=&#8221;xy > x + y&#8221; option2=&#8221;(x + y) < (x + y)\u00b2\" option3=\"x + y < x\u00b2 + y\u00b2\" option4=\"1 + x + y < (1 + x + y)\u00b2\" correct=\"option4\"] This question was previously asked in UPSC ... \n\n<p class=\"read-more-container\"><a title=\"Which one of the following inequalities is always true for positive re\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/#more-89992\">Detailed Solution<span class=\"screen-reader-text\">Which one of the following inequalities is always true for positive re<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1085],"tags":[1098,1102],"class_list":["post-89992","post","type-post","status-publish","format-standard","hentry","category-upsc-capf","tag-1098","tag-quantitative-aptitude-and-reasoning","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Which one of the following inequalities is always true for positive re<\/title>\n<meta name=\"description\" content=\"The correct answer is D) 1 + x + y &lt; (1 + x + y)\u00b2. - The question asks for the inequality that is *always* true for positive real numbers x and y. - A) xy &gt; x + y: If x=1, y=1, 1 &gt; 2 is false. Not always true. - B) (x + y) &lt; (x + y)\u00b2: Let z = x + y. Since x, y &gt; 0, z &gt; 0. The inequality is z &lt; z\u00b2. This is equivalent to z\u00b2 - z &gt; 0, or z(z-1) &gt; 0. Since z &gt; 0, this is true only if z-1 &gt; 0, i.e., z &gt; 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 &lt; (0.2)\u00b2 = 0.04 is false. Not always true. - C) x + y &lt; x\u00b2 + y\u00b2: If x=1, y=1, 1+1 &lt; 1\u00b2+1\u00b2 is 2 &lt; 2, which is false. If x=0.5, y=0.5, 0.5+0.5 &lt; 0.5\u00b2+0.5\u00b2 is 1 &lt; 0.25+0.25=0.5, which is false. Not always true. - D) 1 + x + y &lt; (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x&gt;0, y&gt;0), 1 + x + y must be greater than 1 (w &gt; 1). The inequality becomes w &lt; w\u00b2. This is equivalent to w\u00b2 - w &gt; 0, or w(w-1) &gt; 0. Since w &gt; 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w &lt; w\u00b2 is always true when w &gt; 1. As 1 + x + y &gt; 1 for positive x, y, the inequality 1 + x + y &lt; (1 + x + y)\u00b2 is always true.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following inequalities is always true for positive re\" \/>\n<meta property=\"og:description\" content=\"The correct answer is D) 1 + x + y &lt; (1 + x + y)\u00b2. - The question asks for the inequality that is *always* true for positive real numbers x and y. - A) xy &gt; x + y: If x=1, y=1, 1 &gt; 2 is false. Not always true. - B) (x + y) &lt; (x + y)\u00b2: Let z = x + y. Since x, y &gt; 0, z &gt; 0. The inequality is z &lt; z\u00b2. This is equivalent to z\u00b2 - z &gt; 0, or z(z-1) &gt; 0. Since z &gt; 0, this is true only if z-1 &gt; 0, i.e., z &gt; 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 &lt; (0.2)\u00b2 = 0.04 is false. Not always true. - C) x + y &lt; x\u00b2 + y\u00b2: If x=1, y=1, 1+1 &lt; 1\u00b2+1\u00b2 is 2 &lt; 2, which is false. If x=0.5, y=0.5, 0.5+0.5 &lt; 0.5\u00b2+0.5\u00b2 is 1 &lt; 0.25+0.25=0.5, which is false. Not always true. - D) 1 + x + y &lt; (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x&gt;0, y&gt;0), 1 + x + y must be greater than 1 (w &gt; 1). The inequality becomes w &lt; w\u00b2. This is equivalent to w\u00b2 - w &gt; 0, or w(w-1) &gt; 0. Since w &gt; 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w &lt; w\u00b2 is always true when w &gt; 1. As 1 + x + y &gt; 1 for positive x, y, the inequality 1 + x + y &lt; (1 + x + y)\u00b2 is always true.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T10:18:43+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Which one of the following inequalities is always true for positive re","description":"The correct answer is D) 1 + x + y < (1 + x + y)\u00b2. - The question asks for the inequality that is *always* true for positive real numbers x and y. - A) xy > x + y: If x=1, y=1, 1 > 2 is false. Not always true. - B) (x + y) < (x + y)\u00b2: Let z = x + y. Since x, y > 0, z > 0. The inequality is z < z\u00b2. This is equivalent to z\u00b2 - z > 0, or z(z-1) > 0. Since z > 0, this is true only if z-1 > 0, i.e., z > 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 &lt; (0.2)\u00b2 = 0.04 is false. Not always true. - C) x + y &lt; x\u00b2 + y\u00b2: If x=1, y=1, 1+1 &lt; 1\u00b2+1\u00b2 is 2 &lt; 2, which is false. If x=0.5, y=0.5, 0.5+0.5 &lt; 0.5\u00b2+0.5\u00b2 is 1 &lt; 0.25+0.25=0.5, which is false. Not always true. - D) 1 + x + y < (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x>0, y>0), 1 + x + y must be greater than 1 (w > 1). The inequality becomes w < w\u00b2. This is equivalent to w\u00b2 - w > 0, or w(w-1) > 0. Since w > 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w < w\u00b2 is always true when w > 1. As 1 + x + y > 1 for positive x, y, the inequality 1 + x + y &lt; (1 + x + y)\u00b2 is always true.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following inequalities is always true for positive re","og_description":"The correct answer is D) 1 + x + y < (1 + x + y)\u00b2. - The question asks for the inequality that is *always* true for positive real numbers x and y. - A) xy > x + y: If x=1, y=1, 1 > 2 is false. Not always true. - B) (x + y) < (x + y)\u00b2: Let z = x + y. Since x, y > 0, z > 0. The inequality is z < z\u00b2. This is equivalent to z\u00b2 - z > 0, or z(z-1) > 0. Since z > 0, this is true only if z-1 > 0, i.e., z > 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 &lt; (0.2)\u00b2 = 0.04 is false. Not always true. - C) x + y &lt; x\u00b2 + y\u00b2: If x=1, y=1, 1+1 &lt; 1\u00b2+1\u00b2 is 2 &lt; 2, which is false. If x=0.5, y=0.5, 0.5+0.5 &lt; 0.5\u00b2+0.5\u00b2 is 1 &lt; 0.25+0.25=0.5, which is false. Not always true. - D) 1 + x + y < (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x>0, y>0), 1 + x + y must be greater than 1 (w > 1). The inequality becomes w < w\u00b2. This is equivalent to w\u00b2 - w > 0, or w(w-1) > 0. Since w > 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w < w\u00b2 is always true when w > 1. As 1 + x + y > 1 for positive x, y, the inequality 1 + x + y &lt; (1 + x + y)\u00b2 is always true.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T10:18:43+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/","name":"Which one of the following inequalities is always true for positive re","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T10:18:43+00:00","dateModified":"2025-06-01T10:18:43+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The correct answer is D) 1 + x + y < (1 + x + y)\u00b2. - The question asks for the inequality that is *always* true for positive real numbers x and y. - A) xy > x + y: If x=1, y=1, 1 > 2 is false. Not always true. - B) (x + y) < (x + y)\u00b2: Let z = x + y. Since x, y > 0, z > 0. The inequality is z < z\u00b2. This is equivalent to z\u00b2 - z > 0, or z(z-1) > 0. Since z > 0, this is true only if z-1 > 0, i.e., z > 1. If x=0.1, y=0.1, x+y=0.2, which is not greater than 1. 0.2 &lt; (0.2)\u00b2 = 0.04 is false. Not always true. - C) x + y &lt; x\u00b2 + y\u00b2: If x=1, y=1, 1+1 &lt; 1\u00b2+1\u00b2 is 2 &lt; 2, which is false. If x=0.5, y=0.5, 0.5+0.5 &lt; 0.5\u00b2+0.5\u00b2 is 1 &lt; 0.25+0.25=0.5, which is false. Not always true. - D) 1 + x + y < (1 + x + y)\u00b2: Let w = 1 + x + y. Since x and y are positive real numbers (x>0, y>0), 1 + x + y must be greater than 1 (w > 1). The inequality becomes w < w\u00b2. This is equivalent to w\u00b2 - w > 0, or w(w-1) > 0. Since w > 1, both w and (w-1) are positive. Therefore, their product w(w-1) is always positive. Thus, w < w\u00b2 is always true when w > 1. As 1 + x + y > 1 for positive x, y, the inequality 1 + x + y &lt; (1 + x + y)\u00b2 is always true.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-inequalities-is-always-true-for-positive-re\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CAPF","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-capf\/"},{"@type":"ListItem","position":3,"name":"Which one of the following inequalities is always true for positive re"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/89992","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=89992"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/89992\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=89992"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=89992"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=89992"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}