Question

Найдите двенадцатый член арифметической прогрессии 4,2;3,5;... с полным поеснением

Answer 1

Решение
a₁ = 4,2
d = 3,5 - 4,2 = - 0,7
a₁₂ = a₁ + d(12 - 1) = 4,2 - 0,7*11 = - 3,5
a₁₂ = - 3,5

Answer 2

Finding the 12th term of an arithmetic progression

To find the 12th term of an arithmetic progression, we need to determine the common difference and the first term of the progression.

In this case, the given arithmetic progression is 4.2, 3.5, ...

To find the common difference, we subtract the second term from the first term: 3.5 - 4.2 = -0.7

So, the common difference is -0.7.

To find the first term, we can use the formula for the nth term of an arithmetic progression:

nth term = first term + (n - 1) * common difference

Substituting the values we have: 12th term = first term + (12 - 1) * common difference

Now we can calculate the 12th term:

12th term = 4.2 + (12 - 1) * (-0.7)

Simplifying the expression:

12th term = 4.2 + 11 * (-0.7)

12th term = 4.2 - 7.7

12th term = -3.5

Therefore, the 12th term of the arithmetic progression 4.2, 3.5, ... is -3.5.