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Enzo’s profit over the last few months has been falling. In December he made $900, in January his profit was $500, and in March, he lost $300. Is the sequence that represents his profit arithmetic? If it is, what is the recursive formula for the sequence?

Respuesta :

frika

Answer:

See explanation

Step-by-step explanation:

Enzo’s profit over the last few months:

  • In December, he made profit $900;
  • In January, his his profit was $500;
  • In February - unknown;
  • In March, his loss was  $300.

Find the difference between given data

Dec - Jan [tex]\$900-\$500=\$400[/tex]

Jan - Feb [tex]\$500-\$x[/tex]

Feb - Mar [tex]\$x-(-\$300)=\$x+\$300[/tex]

If this sequence is arithmetic, then

[tex]\$500-\$x=\$x+\$300=\$400\\ \\\$x=\$100[/tex]

So, if the profit in February was $100, then this sequence is arithmetic sequence. In this case,

[tex]a_1=900\\ \\a_2=500\\ \\a_3=100\\ \\a_4=-300\\ \\...\\ \\d=-400[/tex]

The recursive formula is

[tex]a_n=a_{n-1}-400[/tex]