A "Tea Party movement" started during Obama's presidency. This group opposes Obama's health care plan and other policies they see as "big government." Due to the recession, the Tea Party and a dislike of what Obama did, Republicans won a large number of House and Senate seats in the 2010 election. In 2011, Tea Party members of Congress almost shut down the government and sent the U.S. into default (not being able to pay people the government owes money). A few months later, many young people protested against organized and concentrated wealth during the Occupy movement. In 2012, Obama was reelected to a second term. Following reelection, Obama faced major obstruction from Congressional Republicans. This polarization in the political atmosphere and the media, lead to events such as the 2013 Federal Government Shutdown and the stalling of Obama's Supreme Court pick, Judge Merrick Garland to replace Justice Antonio Scalia. In 2014, Republicans took control of both houses of Congress, further adding to the gridlock. In foreign policy, President Obama helped crafted the Paris Climate Agreement, a major global commitment to fighting climate change. He also forged the Iran Nuclear Agreement and opened relations with Cuba for the first time in fifty years.
The United States presidential election, 2016 attracted much attention. Main popular candidates of the election were Republicans Donald Trump and Senator Ted Cruz and Democrats Hillary Clinton and Senator Bernie Sanders. Trump and Clinton won their respective primaries. On November 9, 2016, Trump defeated Clinton. Trump was inaugurated on January 20, 2017. Afterwards, there were many protests against Trump across the country.
On January 27, President Trump signed an executive order that stopped refugees from entering the country for 120 days and denied entry to citizens of Iraq, Iran, Libya, Somalia, Sudan, Syria, and Yemen for 90 days, citing security concerns about terrorism. The next day, thousands of protesters gathered at airports and other locations throughout the United States to protest the signing of the order and detainment of the foreign nationals. Later, the administration seemed to reverse a portion of part of the order, effectively exempting visitors with a green card.
On May 3, 2017, Puerto Rico filed for bankruptcy after a massive debt and weak economy. It is the largest bankruptcy case in American history.
On September 24, 2019, Speaker of the House Nancy Pelosi announced that the House of Representatives would begin an impeachment inquiry into Trump. On October 31, 2019, the House voted 232–196 to created procedures for public hearings. On December 16, the House Judiciary Committee released a report specifying criminal bribery and wire fraud charges as part of the abuse of power charge. The house voted to impeach Trump on December 18, 2019, making him the third president in American history to be impeached.
During most of 2020, the United States was impacted by the COVID-19 pandemic that has impacted the world. The country became the highest infected and the most people dead from the infection. The Trump administration received negative responses for their handling of the virus. Some people refuse to wear surgical masks to help stop the transmission of the virus. In some states, governors locked-down their states in an attempt to stop the spreading of the virus.
Starting in May 2020, racial tensions in the country began to intensify through the police murder of George Floyd causing massive protests and rioting across the country. The Black Lives Matter movement began in grow popularity through mixed reception.
On November 7, 2020 former Vice President Joe Biden defeated President Trump in the country's highest voter turnout presidential election. Biden became the oldest person elected to the office and the first to be from the state of Delaware. Biden's running mate, U.S. Senator Kamala Harris was the first woman, African-American and Asian-American to be elected Vice President or any high-ranking elected office in the country.
On January 6, 2021 while members of the United States Congress met to certify Biden's electoral victory, supporters of President Trump stormed into the United States Capitol attempting to overthrow the results of the 2020 election. Five people died. This led to the United States House of Representatives to impeach Trump for a second time, making him the only U.S. President to be impeached twice.
The United States faces many political issues. One of these is what kind of government the United States should become. Liberals want a large government, while the Tea Party and other groups want a smaller government. One of these debates is over health care. Health care costs have risen. Conservatives and liberals also disagree on social issues such as abortion and gay marriage. Many more people have come to accept gays and gay marriage as an acceptable part of American society. There are also many trends and developments that the U.S. must deal with. One of these is immigration. Many people are coming to the U.S. from Latin America and Asia, especially Mexico. This is called the "browning of America". Baby Boomer Americans are getting older and a larger fraction of the people are retired. Other issues facing the United States are a growing concern about the environment. This has led to the creation of many "green jobs," or jobs that create clean or renewable energy.
Exponential function
In mathematics, the exponential function is a function that grows quicker and quicker. More precisely, it is the function formula_1, where e is Euler's constant, an irrational number that is approximately 2.71828.
Because exponential functions use exponentiation, they follow the same exponent rules. Thus,
This follows the rule that formula_3.
The natural logarithm is the inverse operation of an exponential function, where:
The exponential function satisfies an interesting and important property in differential calculus:
This means that the slope of the exponential function is the exponential function itself, and as a result has a slope of 1 at formula_6. These properties are the reason it is an important function in mathematics.
The general exponential function, where the base is not necessarily formula_7, is among the most useful of mathematical functions. It is used to represent exponential growth, which has uses in virtually all scientific disciplines and is also prominent in finance. Another application of the exponential function is exponential decay, which occurs in radioactive decay and the absorption of light.
One example of an exponential function in real life would be interest in a bank. If a person deposits £100 into an account which gets 3% interest a month, then the balance each month (assuming the money is untouched) would be as follows:
Here, notice how the extra money from interest increases each month, in that the greater the original balance, the more interest the person will get.
Two mathematical examples of exponential functions (with base "a") are shown below.
a=2
a=3
Even though the base (formula_8) can be any number bigger than zero, for example, 10 or 1/2, often it is a special number called e. The number "e" cannot be written exactly, but it is almost equal to 2.71828.
The number "e" is important to every exponential function. For example, a bank pays interest of 0.01 percent every day. One person takes his interest money and puts it in a box. After 10,000 days (about 30 years), he has 2 times as much money as he started with. Another person takes his interest money and puts it back into the bank. Because the bank now pays him interest on his interest, the amount of money is an exponential function.