arithmetic strig

[mathe25]

find the first element(factor a₁) and the arithmetic strig distance if :
a₁+a₂+a₃=18 and a_1*a₂*a₃=162

firs element is a₁
arithmetic strig is a_n​
distance is d

 

[mathe25]

arithmetic

example:1+3+5+6...+157 is the arithmetic strig.
formula for this is a_n=a₁ + (n-1)*d...i must know the steps how u found that a₁ a₂ a₃​ are 3 6 9 ? please help me

 

[yet2spark]

example:1+3+5+6...+157 is the arithmetic strig.
formula for this is a_n=a₁ + (n-1)*d...i must know the steps how u found that a₁ a₂ a₃​ are 3 6 9 ? please help me

So we need to find n

I think it goes between the i and g

 

[mathe25]

can u help me ?

 

[pka]

can u help me ?

You must solve this system.
\(\displaystyle a+(a+d)+(a+2d)=18\)
\(\displaystyle a(a+d)(a+2d)=162\)
for \(\displaystyle a~\&~d\).

 

[yet2spark]

a_1, a_{2 and} a₃ are 3 numbers in an arithmetic progression (strig ?)

a₁+a₂+a<sub>3=18

average =18/3=</sub> a₂₌₆

a₁+a₃₌₁₂
a_1*a_3=162/6=27
=> a_{1=3 and} a₃₌₉

common difference between terms a_3-a₂₌a₁₌a_2-a₁d=3

general term a_n​=3*n​

 

[mathe25]

_{can u show me the steps that u have arrived here} a_{1=3 and} a₃₌₉

 

[pappus]

can u help me ?

1. Have a look here: http://www.freemathhelp.com/forum/threads/75995-help-me-)

By the way: Such double posts are really a waste, a waste of time: My time! I don't like it!

2. As long as you don't show what you've done so far we have to start at the beginning:

In the beginning God created the heaven and the earth. And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.