Answer:
∴ ∑₁⁸i = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8
Step-by-step explanation:
Given:
To Find:
∑₁⁸i =?
Solution:
Σ This symbol called Sigma means "summation up"
∴ ∑ n mean sum for all n
But if ∑₁³n means Sum for n=1 , 2 ,and 3 ADD
∴ ∑₁³n = 1 + 2 + 3
∴ ∑₁⁸i = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8
I think the correct answer from the choices listed above is option A. A limitation of the kinetic-molecular theory for a gas is the <span>theory assumes that particles do not experience intermolecular forces.This cannot be completely true since interactions between particles is normal.</span>
First we note symmetry in the expression's coefficients.
We also note that 7*3=21, and 7+3=10.
From the rational roots theorem, we are tempted to try with 3 and 7 as coefficients of the factors.
Try
(7b+3)(3b+7)=21b^2+(49+9)b+21
By switching the sign of 3b+7 to 3b-7, we get the signs right, to check:
(7b+3)(3b-7)=21b^2+(9-49)b-21=21b^2-40b-21 ....right!
So
(7b+3)(3b-7)=21b^2-40b-21
