Question

A1=16; d=-4; An=-324, знайти n

Answer 1

Ответ:

Объяснение:

$a_{n}=a_{1}+(n-1)d;\\-324=16+(n-1)(-4);\\\\-340=(n-1)(-4);\\\\85=n-1\\n=86$

Answer 2

The formula for the nth term (An) of an arithmetic sequence is given by:

$A_n = A_1 + (n-1)d$

where:

• $A_n$ is the nth term,
• $A_1$ is the first term,
• $d$ is the common difference between terms,
• $n$ is the number of terms.

In your case: $A_n = -324$ $A_1 = 16$ $d = -4$

Substitute these values into the formula: $-324 = 16 + (n-1)(-4)$

Now, solve for $n$:

$-324 = 16 - 4n + 4$

Combine like terms: $-324 = 20 - 4n$

Subtract 20 from both sides: $-344 = -4n$

Divide by -4 to isolate $n$: $n = 86$

So, $n = 86$.