{"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":155,"title":"All your base are belong to us","description":"Find the base _b_ logarithm of the input decimal number _x_. Express the output as a decimal number. The first argument is the number _x_, and the second argument is the base _b_.\r\n\r\nExamples\r\n\r\n logb(1024,2)    ---\u003e 10\r\n\r\n logb(25,5)      ---\u003e  2\r\n \r\n logb(100000,10) ---\u003e  5","description_html":"\u003cp\u003eFind the base \u003ci\u003eb\u003c/i\u003e logarithm of the input decimal number \u003ci\u003ex\u003c/i\u003e. Express the output as a decimal number. The first argument is the number \u003ci\u003ex\u003c/i\u003e, and the second argument is the base \u003ci\u003eb\u003c/i\u003e.\u003c/p\u003e\u003cp\u003eExamples\u003c/p\u003e\u003cpre\u003e logb(1024,2)    ---\u0026gt; 10\u003c/pre\u003e\u003cpre\u003e logb(25,5)      ---\u0026gt;  2\u003c/pre\u003e\u003cpre\u003e logb(100000,10) ---\u0026gt;  5\u003c/pre\u003e","function_template":"function y = logb(x,b)\r\n  y = 7;\r\nend","test_suite":"%%\r\nx = 1024;\r\nb = 2;\r\ny_correct = 10;\r\nassert(isequal(logb(x,b),y_correct))\r\n\r\n%%\r\nx = 25;\r\nb = 5;\r\ny_correct = 2;\r\nassert(isequal(logb(x,b),y_correct))\r\n\r\n\r\n%%\r\nx = 10000;\r\nb = 10;\r\ny_correct = 4;\r\nassert(isequal(logb(x,b),y_correct))\r\n","published":true,"deleted":false,"likes_count":5,"comments_count":0,"created_by":39,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":579,"test_suite_updated_at":"2012-01-29T03:14:42.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-01-29T03:14:42.000Z","updated_at":"2026-05-18T12:31:11.000Z","published_at":"2012-01-29T03:21:05.000Z","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\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"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\\n\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\u003eFind the base\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eb\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e logarithm of the input decimal number\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ex\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e. Express the output as a decimal number. The first argument is the number\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ex\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, and the second argument is the base\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eb\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExamples\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[ logb(1024,2)    ---\u003e 10\\n\\n logb(25,5)      ---\u003e  2\\n\\n logb(100000,10) ---\u003e  5]]\u003e\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":155,"title":"All your base are belong to us","description":"Find the base _b_ logarithm of the input decimal number _x_. Express the output as a decimal number. The first argument is the number _x_, and the second argument is the base _b_.\r\n\r\nExamples\r\n\r\n logb(1024,2)    ---\u003e 10\r\n\r\n logb(25,5)      ---\u003e  2\r\n \r\n logb(100000,10) ---\u003e  5","description_html":"\u003cp\u003eFind the base \u003ci\u003eb\u003c/i\u003e logarithm of the input decimal number \u003ci\u003ex\u003c/i\u003e. Express the output as a decimal number. The first argument is the number \u003ci\u003ex\u003c/i\u003e, and the second argument is the base \u003ci\u003eb\u003c/i\u003e.\u003c/p\u003e\u003cp\u003eExamples\u003c/p\u003e\u003cpre\u003e logb(1024,2)    ---\u0026gt; 10\u003c/pre\u003e\u003cpre\u003e logb(25,5)      ---\u0026gt;  2\u003c/pre\u003e\u003cpre\u003e logb(100000,10) ---\u0026gt;  5\u003c/pre\u003e","function_template":"function y = logb(x,b)\r\n  y = 7;\r\nend","test_suite":"%%\r\nx = 1024;\r\nb = 2;\r\ny_correct = 10;\r\nassert(isequal(logb(x,b),y_correct))\r\n\r\n%%\r\nx = 25;\r\nb = 5;\r\ny_correct = 2;\r\nassert(isequal(logb(x,b),y_correct))\r\n\r\n\r\n%%\r\nx = 10000;\r\nb = 10;\r\ny_correct = 4;\r\nassert(isequal(logb(x,b),y_correct))\r\n","published":true,"deleted":false,"likes_count":5,"comments_count":0,"created_by":39,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":579,"test_suite_updated_at":"2012-01-29T03:14:42.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-01-29T03:14:42.000Z","updated_at":"2026-05-18T12:31:11.000Z","published_at":"2012-01-29T03:21:05.000Z","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\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"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\\n\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\u003eFind the base\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eb\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e logarithm of the input decimal number\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ex\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e. Express the output as a decimal number. The first argument is the number\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ex\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, and the second argument is the base\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eb\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExamples\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[ logb(1024,2)    ---\u003e 10\\n\\n logb(25,5)      ---\u003e  2\\n\\n logb(100000,10) ---\u003e  5]]\u003e\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":"easy","count":1,"selected":false}]],"term":"tag:\"logarithm base\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}