How do we actually calculate this?

Maxim19

New member
Joined
Mar 22, 2019
Messages
4
Hello!

I'd like to know how do we calculate manually this following operation :

[(1-2.8)^2*1+(2-2.8)^2*3+(3-2.8)^2*2+(4-2.8)^2*2+(5-2.8)^2*1]/10=?

More specifically I'm interested in knowing how do we break down the numbers in brackets that are to the power of two such as (1-2.8)^2*1+(2-2.8)^2*3 etc, because no matter in what way I try to do it by myself without the help of a calculator the results do not coincide unfortunately.

Your help would be greatly appreciated!
 

ksdhart2

Senior Member
Joined
Mar 25, 2016
Messages
1,054
Given that everything involved here is "actual" numbers and not variables, what's stopping you from just cranking it through on pen & paper? Begin by discarding the *1's as multiplying by 1 does nothing:

\(\displaystyle \frac{(1-2.8)^2+(2-2.8)^2 \cdot 3+(3-2.8)^2 \cdot 2+(4-2.8)^2 \cdot 2+(5-2.8)^2}{10}\)

Then evaluate it step-by-step, according to PEMDAS. The first step is to resolve anything in Parentheses. Let's do that now:

\(\displaystyle \frac{(-1.8)^2+(-0.8)^2 \cdot 3+0.2^2 \cdot 2+1.2^2 \cdot 2+2.2^2}{10}\)

The next step is to resolve any Exponents. Your turn to try. What do you get here? As a hint, consider what exponents mean, specifically when the power is an integer. A refresher on exponents can be found here if needed
 

Maxim19

New member
Joined
Mar 22, 2019
Messages
4
Given that everything involved here is "actual" numbers and not variables, what's stopping you from just cranking it through on pen & paper? Begin by discarding the *1's as multiplying by 1 does nothing:

\(\displaystyle \frac{(1-2.8)^2+(2-2.8)^2 \cdot 3+(3-2.8)^2 \cdot 2+(4-2.8)^2 \cdot 2+(5-2.8)^2}{10}\)

Then evaluate it step-by-step, according to PEMDAS. The first step is to resolve anything in Parentheses. Let's do that now:

\(\displaystyle \frac{(-1.8)^2+(-0.8)^2 \cdot 3+0.2^2 \cdot 2+1.2^2 \cdot 2+2.2^2}{10}\)

The next step is to resolve any Exponents. Your turn to try. What do you get here? As a hint, consider what exponents mean, specifically when the power is an integer. A refresher on exponents can be found here if needed
Thank you it helped a lot!
 

Denis

Senior Member
Joined
Feb 17, 2004
Messages
1,652
I'd like to know how do we calculate manually this following operation :

[(1-2.8)^2*1+(2-2.8)^2*3+(3-2.8)^2*2+(4-2.8)^2*2+(5-2.8)^2*1]/10=?

More specifically I'm interested in knowing how do we break down the numbers in brackets
that are to the power of two such as (1-2.8)^2*1+(2-2.8)^2*3 etc, because no matter in what
way I try to do it by myself without the help of a calculator the results do not coincide unfortunately.
WHAT are you really asking?
How to calculate (as example) 3 * (2 - 2.8)^2 BY HAND ?
WHY?
 
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