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Alex Worked At K-Mart - September 6, 2009
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Spiked Math Comic - Alex Worked At K-Mart

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haha, I laughed at this xD
yes... I'm a nerd 8-)

To be honest, I'm getting tired of the rational/complex/irrational/natural number jokes.

$18 for a shirt? Is that cheap or expensive?

Hmmmm let's see now....

( sqrt(2) + sqrt(8) )^2
= sqrt(2)^2 + sqrt(8)^2 + 2( sqrt(2) * sqrt(8) )
= 2 + 8 + 2( sqrt(16) )
= 2 + 8 + 2( +/- 4 )
= 2 + 8 +/- 8

so it's either $18 or $2 :)

By definition, sqrt(16) is 4, not +/-4. $18 is the unambiguous price.

r u nuts or have u lost it..??
its plain $18

sqrt 8 = 2sqrt2
sqrt 2 + sqrt 8 = 3sqrt2

so (sqrt 2 + sqrt 8)^2 = (3sqrt2)^2 = 18

uhh dude, whats with the +/-4 ???? sqrt(16) is just 4 ......

Wow people why are you here if you don't understand this kind of math. (-4)(-4)=(4)(4)=16 so sqrt(16)=+/-4 (+ or -4). Sqrt(16) is byy no means defined as +4.

The principal squareroot, which is referred to as "the square root", of x is defined as the POSITIVE number which multiplied by itself gives x. You probably confused it with the fact that the solution to the equation x^2=y is x=+/-sqrt(y). As you can see, we put the "+/-" outside the squareroot because, as said earlier, sqrt(x^2)=|x|. If you don't believe me check out this: http://www.purplemath.com/modules/radicals.htm (Made specifically for kids)

Yes, but for the intents and purposes of a high school math class or above square root it's plus or minus.

Difference: x^2 = 16 -> x = 4 OR x = -4. sqrt(16) = 4.
Sqrt(x) is a FUNCTION that spits out the unique positive square root. The other question is, "What is x such that x^2 = 16?". Then the answer would be 4 or -4.

While this joke and its ilk are so old, really, what choice do amateur math humorists have?

pi-rate jokes? Please. Those are so 2008.


This reminds me of when the show candid camera put up a sign next to a pile of shirts at a clothing store that said "110% Off!" They went through the confused ppl and laughed and everything. But then this one lady came on and said that she automatically knew it was a fake. They asked how, and she said "I'm a math teacher, so I'd know that 110% is impossible."

Personally, what I think she failed to think is that anything more than 100% off actually means that the "seller" pays (x-100)% to the "buyer" to purchase the product. I was mad. :D

Better yet, make a sale saying:

Our prices have 300% off and then again 300% off! :o)

Not only is it rational, it's a natural price!


= [sqrt(2) +/- 2sqrt(2)]^2
= [(1 +/- 2)sqrt(2)]^2
= (1 +/- 2)^2 *2
= (3^2)*2 or ((-1)^2)*2
= 18 or 2
= gpm982 is absolutely correct

This is super cool!
Rational in here could be mean literally (the price is rational, $2) and rational square root :D

Hahaha very droll!

Ad alert.

the shirt is $10 because when you have (SqrRt2 + SqrRt8)Squared you square the inside of the brackets first and it takes away the square root giving you 2+8=10 you cant have two possible answers in price for 1 shirt unless there is a %off on the shirt at a diffrent time

No. Bad math. It's not 2+8 when you square inside the brackets.

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Hello my fellow math geeks. My name is Mike and I am the creator of Spiked Math Comics, a math comic dedicated to humor, educate and entertain the geek in you. Beware though, there might be some math involved :D

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