1, 3,6, 10, 15, 2 1, there is a formula for this kind of problem, which is the general term formula of the sequence. Details are as follows:

Solution:

List 1, 3, 6, 10,,, an,

a2-a 1=2，

a3-a2=3，

a4-a3=4，

:::

an-a(n- 1)=n，

It can be concluded that all the above additions and subtractions are an-a1= 2+3+4+…+an =1+2+3+4+…+n = n (n+1)/2.

Characteristics of wrong mathematical formula

1, claiming to be scientific, is vague and lacks specific weights and measures.

2. Operation definitions (for example, public variables, ownership or objects that outsiders can also check) cannot be used.

3, can not meet the principle of simplicity, that is, when many variables appear, can not get the answer from the simplest way.

4. Use ambiguous language and a lot of technical terms to make the article look scientific.

Refer to the above information? Baidu Encyclopedia-Mathematical Formula