`); }); } $('#search-pretype-options').append(prevbooks); }); } function anon_pretype() { let prebooks = null; try { prebooks = JSON.parse(localStorage.getItem('PRETYPE_BOOKS_ANON')); }catch(e) {} if ('previous_books' in prebooks && 'recommended_books' in prebooks) { previous_books = prebooks.previous_books; recommended_books = prebooks.recommended_books; if (typeof PREVBOOKS !== 'undefined' && Array.isArray(PREVBOOKS)) { new_prevbooks = PREVBOOKS; previous_books.forEach(elem => { for (let i = 0; i < new_prevbooks.length; i++) { if (elem.id == new_prevbooks[i].id) { return; } } new_prevbooks.push(elem); }); new_prevbooks = new_prevbooks.slice(0,3); previous_books = new_prevbooks; } if (typeof RECBOOKS !== 'undefined' && Array.isArray(RECBOOKS)) { new_recbooks = RECBOOKS; for (let j = 0; j < new_recbooks.length; j++) { new_recbooks[j].viewed_at = new Date(); } let insert = true; for (let i=0; i < recommended_books.length; i++){ for (let j = 0; j < new_recbooks.length; j++) { if (recommended_books[i].id == new_recbooks[j].id) { insert = false; } } if (insert){ new_recbooks.push(recommended_books[i]); } } new_recbooks.sort((a,b)=>{ adate = new Date(2000, 0, 1); bdate = new Date(2000, 0, 1); if ('viewed_at' in a) {adate = new Date(a.viewed_at);} if ('viewed_at' in b) {bdate = new Date(b.viewed_at);} // 100000000: instead of just erasing the suggestions from previous week, // we just move them to the back of the queue acurweek = ((new Date()).getDate()-adate.getDate()>7)?0:100000000; bcurweek = ((new Date()).getDate()-bdate.getDate()>7)?0:100000000; aviews = 0; bviews = 0; if ('views' in a) {aviews = acurweek+a.views;} if ('views' in b) {bviews = bcurweek+b.views;} return bviews - aviews; }); new_recbooks = new_recbooks.slice(0,3); recommended_books = new_recbooks; } localStorage.setItem('PRETYPE_BOOKS_ANON', JSON.stringify({ previous_books: previous_books, recommended_books: recommended_books })); build_popup(); } } var whiletyping_search_object = null; var whiletyping_search = { books: [], curriculum: [], topics: [] } var single_whiletyping_ajax_promise = null; var whiletyping_database_initial_burst = 0; //number of consecutive calls, after 3 we start the 1 per 5 min calls function get_whiletyping_database() { //gets the database from the server. // 1. by validating against a local database value we confirm that the framework is working and // reduce the ammount of continuous calls produced by errors to 1 per 5 minutes. return localforage.getItem('whiletyping_last_attempt').then(function(value) { if ( value==null || (new Date()) - (new Date(value)) > 1000*60*5 || (whiletyping_database_initial_burst < 3) ) { localforage.setItem('whiletyping_last_attempt', (new Date()).getTime()); // 2. Make an ajax call to the server and get the search database. let databaseUrl = `/search/whiletype_database/`; let resp = single_whiletyping_ajax_promise; if (resp === null) { whiletyping_database_initial_burst = whiletyping_database_initial_burst + 1; single_whiletyping_ajax_promise = resp = new Promise((resolve, reject) => { $.ajax({ url: databaseUrl, type: 'POST', data:{csrfmiddlewaretoken: "SBHXKv5yXmz5rpNqc1FfE1mpdvKq4jDtIU3tRbh8Sv65kiYIj6ZGgJAJKw9LpR2F"}, success: function (data) { // 3. verify that the elements of the database exist and are arrays if ( ('books' in data) && ('curriculum' in data) && ('topics' in data) && Array.isArray(data.books) && Array.isArray(data.curriculum) && Array.isArray(data.topics)) { localforage.setItem('whiletyping_last_success', (new Date()).getTime()); localforage.setItem('whiletyping_database', data); resolve(data); } }, error: function (error) { console.log(error); resolve(null); }, complete: function (data) { single_whiletyping_ajax_promise = null; } }) }); } return resp; } return Promise.resolve(null); }).catch(function(err) { console.log(err); return Promise.resolve(null); }); } function get_whiletyping_search_object() { // gets the fuse objects that will be in charge of the search if (whiletyping_search_object){ return Promise.resolve(whiletyping_search_object); } database_promise = localforage.getItem('whiletyping_database').then(function(database) { return localforage.getItem('whiletyping_last_success').then(function(last_success) { if (database==null || (new Date()) - (new Date(last_success)) > 1000*60*60*24*30 || (new Date('2023-04-25T00:00:00')) - (new Date(last_success)) > 0) { // New database update return get_whiletyping_database().then(function(new_database) { if (new_database) { database = new_database; } return database; }); } else { return Promise.resolve(database); } }); }); return database_promise.then(function(database) { if (database) { const options = { isCaseSensitive: false, includeScore: true, shouldSort: true, // includeMatches: false, // findAllMatches: false, // minMatchCharLength: 1, // location: 0, threshold: 0.2, // distance: 100, // useExtendedSearch: false, ignoreLocation: true, // ignoreFieldNorm: false, // fieldNormWeight: 1, keys: [ "title" ] }; let curriculum_index={}; let topics_index={}; database.curriculum.forEach(c => curriculum_index[c.id]=c); database.topics.forEach(t => topics_index[t.id]=t); for (j=0; j
(b.item.view_count || 0) - (a.item.view_count || 0)); whiletyping_search = {books: [], curriculum: [], topics: []}; const MAX_BOOKS=3; const MAX_COURSES=4; const MAX_TOPICS=6; let curriculum_titles = new Set(); let topics_titles = new Set(); add_without_repetition = (params)=>{ // insert items from elems into array checking that array is max size // and no title duplicates for (var i = 0; i=params.max) {break;} if (!params.titles.has(params.elems[i].item.title)){ params.titles.add(params.elems[i].item.title); params.array.push(params.elems[i].item); } } } add_without_repetition({ max: MAX_COURSES, titles: curriculum_titles, elems: curriculum, array: whiletyping_search.curriculum }); add_without_repetition({ max: MAX_TOPICS, titles: topics_titles, elems: topics, array: whiletyping_search.topics }); for (var i = 0; i=MAX_BOOKS) {break;} book = books[i].item; whiletyping_search.books.push(book); add_without_repetition({ max: MAX_COURSES, titles: curriculum_titles, elems: book.curriculum, array: whiletyping_search.curriculum }); add_without_repetition({ max: MAX_TOPICS, titles: topics_titles, elems: book.topics, array: whiletyping_search.topics }); } return true; } else { return false; } }); } function build_solutions() { if (Array.isArray(solution_search_result)) { const viewAllHTML = userSubscribed ? `View All` : ''; var solutions_section = $(`
Solutions ${viewAllHTML}
`); let questionUrl = "/questions/xxx/"; let askUrl = "/ask/question/xxx/"; solution_search_result.forEach((elem) => { let url = ('course' in elem)?askUrl:questionUrl; let solution_type = ('course' in elem)?'ask':'question'; let subtitle = ('course' in elem)?(elem.course??""):(elem.book ?? "")+" "+(elem.chapter?"Chapter "+elem.chapter:""); solutions_section.find('#whiletyping-solutions').append(` ${elem.text} ${subtitle} `); }); $('#search-solution-options').empty(); if (Array.isArray(solution_search_result) && solution_search_result.length>0){ $('#search-solution-options').append(solutions_section); } MathJax.Hub.Queue(["Typeset", MathJax.Hub, document.getElementById('search-solution-options')]); } } function build_whiletyping() { $('#search-pretype-options').empty(); $('#search-pretype-options').append($('#search-solution-options').html()); if (Array.isArray(whiletyping_search.books) && whiletyping_search.books.length>0) { var books_section = $(`
The domestic demand for portable radios is given by Q = 5 , 000 − 100 P where price is measured in dollars and quantity is measured in thousands of radios per year. The domestic supply curve for radios is given by Q = 150 P a.
The demand function for a type of portable radio is given by the model d=85−6x2, where d is measured in dollars and x is measured in millions of units.
The consumer surplus in a market is represented by the area below the demand curve and above the market price. In our market for oranges, this is the shaded triangle, labeled A in Figure 1 .
A demand function in managerial economics is a mathematical expression revealing the relationship between the quantity of a good or service that customers are willing and able to purchase, and its determinants such as price, income level, tastes and prices of related goods or services.
The demand function takes the form Qd= a – bP, and this states how the price (P) of a good or service determines the quantity demanded (Qd). Some basics: Qd = quantity demanded. a = the quantity demanded when the price = 0 (because b x 0 = 0)
(A) Receive the incoming modulated carrier by the antenna. (B) Select the wanted signal and reject the unwanted signal and the noise. (C) Detection and amplification of the information signal from the carrier.
radio, a form of mass media and sound communication by radio waves, usually through the transmission of music, news, and other types of programs from single broadcast stations to multitudes of individual listeners equipped with radio receivers.
For example, if the demand function is a simple linear function with only the price as input: Qd = 1000 - 0.5P, then, if the disposable income increases, there will be a shift in the demand curve and a change in the demand function. The new demand function can be Qd = 1100 - 0.5P.
A demand function is a mathematical function describing the relationship between a variable, like the demand of quantity, and various factors determining the demand. The purpose of this function is to analyze the behavior of consumers in a market and to help firms make pricing decisions.
Introduction: My name is Jonah Leffler, I am a determined, faithful, outstanding, inexpensive, cheerful, determined, smiling person who loves writing and wants to share my knowledge and understanding with you.
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