What was going on when I was born?

THE economy is rocky and the price of hotel rooms is beyond many budgets, but New York continues to be a magnet for the rest of the country and, indeed, the world. To an increasing number of visitors the solution is simple: stay with a friend. For New Yorkers, no matter how hospitably minded, it isn't quite so easy. Large apartments are the exception rather than the norm, and the scale and price of many newer apartments precludes nonessential space. Most brownstones, once occupied by single families, have been broken into individual apartments. Manhattan residents would agree that space has become one of the city's great luxuries. Nevertheless, New Yorkers are an ingenious lot, and rather than forgo the pleasure of seeing friends from out of town, many have come up with sleeping facilities scarcely larger than the size of a reclining body. Others, more traditionally minded, have put convertible sleep sofas in rooms ranging from libraries and dining rooms to home offices.

The Eastman Kodak Company yesterday introduced a line of cameras that use a film disk instead of conventional roll film. The new products are intended to secure the company's position as the dominant force in amateur photography for the rest of the decade. Foreshadowed in patent drawings and research disclosures during the past few years, the introduction included no surprises but was still impressive, according to industry analysts. The disk cameras are ''the biggest innovation in amateur photography since the cartridge-loading Instamatic was introduced 19 years ago,'' Walter Fallon, the company's chairman, unabashedly told reporters gathered at the Plaza Hotel yesterday. The meeting was one of eight news conferences the company held around the world.

President Hosni Mubarak of Egypt told President Reagan today that solving the Palestinian problem was the ''key to peace'' in the Middle East. He said the Palestinians could not be denied ''the right to self-determination'' and formation of ''a national entity.'' In formal remarks at the White House, marking his first visit here since becoming President after the assassination of Anwar el-Sadat last October, Mr. Mubarak did not mention the negotiations with Israel for self-rule for Palestinians living in the occupied West Bank and Gaza Strip. Nor did he mention the Camp David agreements of 1978 that led to the 1979 peace treaty between Egypt and Israel and the talks on self-rule.

Governor Carey plans to ask the Legislature to increase the state's sales tax to provide more money for education, top aides to the Governor said today. But they said he would link his request to changes in the income tax designed to provide relief for New Yorkers with low incomes, Word of the proposal came as Mr. Carey's Commerce Commissioner, George Dempster, gave a speech in New York City calling for incometax reductions and Assembly Speaker Stanley Fink called on the Legislature to enact income-tax cuts this year that would take effect later in the decade. Mr. Carey, in the meantime, held a news conference at which he said that while the state could not afford tax reductions in its current budget, he would not be opposed to ''down-range'' income-tax cuts. Help for Poor Districts The increased spending for education is aimed at reducing disparities between rich and poor school districts, as required in a series of court decisions involving the school district in Levittown, L.I., and other districts in the state.

Congress appears to be increasingly divided over the decision to send more aid to El Salvador, but for the moment the Administration seems to have majority support for its policy of trying to prevent the overthrow of the Salvadoran Government. At a news conference today, Speaker Thomas P. O'Neill Jr. said, ''I hear some rising objections to what Haig is doing from within the Democratic Party and from my area at home.'' But his fellow Democrat, Representative Jim Wright of Texas, the majority leader, said in an interview, ''I agree with the Administration position, and I very actively oppose any effort to withhold assistance to the moderate Government of Duarte.'' Two Unappealing Choices Perhaps the most frequent reaction on Capitol Hill, however, was expressed by Senator J. James Exon, Democrat of Nebraska, who said the United States had two unappealing choices. ''If we turn down the additional aid,'' he said, ''we could be helping the Communist guerrilla takeover of the country. But on the other hand, we'd be aiding a Government we're not happy with. The bottom line is, which is the lesser of two evils?''

A Business Day article in some edi- tions yesterday incorrectly quoted Treasury Secr etary Donald T. Regan on natural ga s deregulation. Mr. Regan said, ' 'At the current moment the President is not going to propose deregulation of n atural gas or a wind- fall profits tax.''

''The exercise of the right to self-determination cannot be denied to the Palestinian people.

Howard H. Baker Jr., the Senate majority leader, said today there were ''preliminary indications'' that the White House would accept a joint resolution of Congress, rather than new legislation, opposing tax exemptions for private schools that practice racial discrimination. President Reagan has asked for legislation forbidding tax exemptions for such schools, and Senator Baker, a Tennessee Republican, said White House officials still preferred that approach. But he said most senators believed no legislation was needed because existing law gave the Internal Revenue Service authority to deny such exemptions. In effect, the senators took issue with Mr. Reagan's contention at his Jan. 19 news conference that an Internal Revenue Service ruling barring exemptions to those schools ''had no basis in law'' and that the agency ''had actually formed a social law and was enforcing that social law.''

TO those students thinking about summer jobs this year - and now is a good time to begin - the big question concerns job availability. What are the chances o f landing a decent summ er job in a recession market? The answer, according to economists a nd labor specialists, isthat conditions are uncertain. On the negative side it appears that there will be fewer openings, at least as far as Federal Government summer jobs are concerned. ''It's hard to predict exactly the percentage of cutbacks over last year,'' said Barbara Arnelle, a staffing specialist in the United States Office of Personnel Management. ''But you can get a sense of the trend by looking at recent figures.''

International A major policy split on Poland's debts was reported in the Reagan Administration. High Pentagon officials said that Defense Secretary Caspar W. Weinberger intended to keep pressing to have Poland declared in default of its debts to the West and to prod Western European nations to halt their natural gas pipeline deal with Moscow. (Page A1, Column 6.) A group of hard-liners in Warsaw has emerged among Poland's rulers, Polish sources said. The strong conservative faction, they said, opposes any political reform, a revival of Solidarity as an independent union and any talks with Lech Walesa. (A3:1-3.)

For wealthy investors who managed to outsmart the market and sell their stocks or bonds at a profit last year, one of the biggest breaks of the new tax law is the retroactive cut in the top capital gains rate. The law slashed to 20 percent from 28 percent the maximum tax on net long-term capital gains, effective for transactions that took place after June 9, 1981. But this dramatic rate cut benefits only those affluent individuals whose tax brackets exceed 50 percent. ''For many people in lower brackets, nothing has really changed,'' said G. William Clapp, a tax partner with the accounting firm of Deloitte Haskins & Sells. ''But for high-bracket taxpayers, the benefit will be significant.''

Secretary of Defense Caspar W. Weinberger reportedly intends to keep pressing to have Poland declared in default of its debts to the West and to have Western European nations halt their natural gas pipeline deal with Moscow. On the recommendation of the State, Treasury and Agriculture Departments, President Reagan recently agreed to have the Administration pay American banks the $71 million owed them by Poland to forestall a declaration of default and a possible disruption of East-West economic relations. But, in the continuing debate on the question within the Administration, high Pentagon officials oppose this action. They insist that the issue of Polish default has n ot been finally settled.Mr. Weinberger is known to favor the tougher stance of allowing default and the disruption of Western credit relations with the East so as to impose an economic penalty on Moscow and Warsaw for the repression in Poland.