Solution process: substitute I = 1, 2, 3, 4, 5, 6, 7 into infinite N to form I? -1, and then sum.

Capital σ is used for mathematical summation symbols, such as ∑Pi, where i= 1, 2, ..., t, which is the sum of P 1+P2+ and ...+angle.

Get the result:

Extended data

Detailed explanation and application of summation formula

1, the ∑ symbol means sum, and ∑ is pronounced as sigma, which means sum in English and is the sum.

The method of summing with sigma is called Sigma Notation. Its lowercase is σ, in kind.

Theoretically, it is often used to express area density. (Therefore, ρ stands for bulk density and η stands for linear density)

2. The usage of ∑:

Where I stands for the lower bound, n stands for the upper bound, and k starts from I and goes all the way to n, all of which add up.

∑ i can also be expressed as the sum of I, which is a variable.

References:

Baidu encyclopedia √