{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":1206,"title":"Angles of the hands of a clock","description":"For this problem, consider an analog (or at least continuous digital representation) of a clock.  Our clock is a 12 hour clock with an hour, minute, and second hand.\r\n\r\nYou'll receive a row vector that is [hours minutes seconds].  For this input time, determine the angles between the hands of the clock.  All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times.  No error checking is required.\r\n\r\nYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\r\n\r\nWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.","description_html":"\u003cp\u003eFor this problem, consider an analog (or at least continuous digital representation) of a clock.  Our clock is a 12 hour clock with an hour, minute, and second hand.\u003c/p\u003e\u003cp\u003eYou'll receive a row vector that is [hours minutes seconds].  For this input time, determine the angles between the hands of the clock.  All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times.  No error checking is required.\u003c/p\u003e\u003cp\u003eYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\u003c/p\u003e\u003cp\u003eWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.\u003c/p\u003e","function_template":"% t = [hour minute second]\r\nfunction angDiffs = clockHandAngDifferences(t)\r\n  % angDiffs = [ (hour angle - minute angle) (minute angle - seconds angle) }\r\n  angDiffs  = t;\r\nend","test_suite":"%%\r\nt=[7 30 15];\r\nt_correct = [43.625  91.5];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);\r\n%%\r\nt=[11 59 59];\r\nt_correct = [0.0916666666666401 5.89999999999998];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);\r\n%%\r\nt=[3 45 50];\r\nt_correct = [-162.083333333333 -25];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":2193,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":38,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2013-01-16T18:44:35.000Z","updated_at":"2026-05-26T16:50:02.000Z","published_at":"2013-01-16T19:03:27.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor this problem, consider an analog (or at least continuous digital representation) of a clock. Our clock is a 12 hour clock with an hour, minute, and second hand.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou'll receive a row vector that is [hours minutes seconds]. For this input time, determine the angles between the hands of the clock. All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times. No error checking is required.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":1206,"title":"Angles of the hands of a clock","description":"For this problem, consider an analog (or at least continuous digital representation) of a clock.  Our clock is a 12 hour clock with an hour, minute, and second hand.\r\n\r\nYou'll receive a row vector that is [hours minutes seconds].  For this input time, determine the angles between the hands of the clock.  All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times.  No error checking is required.\r\n\r\nYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\r\n\r\nWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.","description_html":"\u003cp\u003eFor this problem, consider an analog (or at least continuous digital representation) of a clock.  Our clock is a 12 hour clock with an hour, minute, and second hand.\u003c/p\u003e\u003cp\u003eYou'll receive a row vector that is [hours minutes seconds].  For this input time, determine the angles between the hands of the clock.  All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times.  No error checking is required.\u003c/p\u003e\u003cp\u003eYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\u003c/p\u003e\u003cp\u003eWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.\u003c/p\u003e","function_template":"% t = [hour minute second]\r\nfunction angDiffs = clockHandAngDifferences(t)\r\n  % angDiffs = [ (hour angle - minute angle) (minute angle - seconds angle) }\r\n  angDiffs  = t;\r\nend","test_suite":"%%\r\nt=[7 30 15];\r\nt_correct = [43.625  91.5];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);\r\n%%\r\nt=[11 59 59];\r\nt_correct = [0.0916666666666401 5.89999999999998];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);\r\n%%\r\nt=[3 45 50];\r\nt_correct = [-162.083333333333 -25];\r\nassert(max(abs(clockHandAngDifferences(t)-t_correct))\u003c1e-10);","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":2193,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":38,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2013-01-16T18:44:35.000Z","updated_at":"2026-05-26T16:50:02.000Z","published_at":"2013-01-16T19:03:27.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor this problem, consider an analog (or at least continuous digital representation) of a clock. Our clock is a 12 hour clock with an hour, minute, and second hand.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou'll receive a row vector that is [hours minutes seconds]. For this input time, determine the angles between the hands of the clock. All times for the clock will be times before 12:00:00, and all hour minute and second entries will correspond with real times. No error checking is required.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou need to provide a two element row vector that is, in degrees, [(angle between hour and minute hand) (angle between minute and second hand)].\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWhile not terribly hard, the problem is a bit trickier than it will appear to many at first glance.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"time clock\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}