Billie Jean has $120 to spend and wants to buy either a new amplifier for her guitar or a new mp3 player to listen to music while working out. Both the amplifier and the mp3 player cost $120, so she can only buy one. This illustrates the basic concept that

Rational people make decisions at the margin by

Representatives of the public have launched a public campaign against the Minister, demanding more transparent ministry action and taking into account their suggestions for adjusting the ministry's policy, which was developed with your direct participation. How should information be made available to the public? Give examples of material that should be made public.

Candice is planning her activities for a hot summer day. She would like to go to the local swimming pool and see the latest blockbuster movie, but because she can only get tickets to the movie for the same time that the pool is open she can only choose one activity. This illustrates the basic principle that

Economists make assumptions to

Jelölje be a lefutó aggregáló lekérdezéseket, amelyek nem adnak 'not a GROUP BY expression' hibát!

Jelölje be azokat a parancsokat, amelyek  primary key constaint-et/elsődleges kulcs megszorítást sértenek! (A parancsokat külön tekintve, az eredeti adatbázison lefuttatva.)

Jelölje be azokat a parancsokat, amelyek  foreign key constraint-et/külső kulcs megszorítást sértenek! (A parancsokat külön tekintve, az eredeti adatbázison lefuttatva.)

There are two vectors 𝒂 and 𝒃 originating from the same point.

• Vector 𝒂 points 3 units to the right and 4 units up.
• Vector 𝒃 points 5 units to the right and 2 units up.

Find the magnitude of the cross product |𝒂 × 𝒃|.