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pandaexpress
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When multiplying x2 and x5, we get x7. Quick, dumb question:
Why isn't it x10 instead (since we're multiplying and not adding)?
Why isn't it x10 instead (since we're multiplying and not adding)?
##x^2## means ##x \cdot x##, and ##x^2## means ##x \cdot x \cdot x \cdot x \cdot x##, so ##x^2 \cdot x^5## means ##x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot x##, right? How many factors of x are there in that last expression?pandaexpress said:When multiplying x2 and x5, we get x7. Quick, dumb question:
Why isn't it x10 instead (since we're multiplying and not adding)?
jedishrfu said:Think of the exponent as counting the number of factors so x^2 is x*x and x^5 is x*x*x*x*x and when multiplied together gives you 7 x's or x^7
No.pandaexpress said:This might seem a little dumb, but I figured that multiplying would give you 10 still. Using your example above,
x2 = x*x
x5 = x*x*x*x*x
Wouldn't x2 * x5 = x*x; x*x; x*x; x*x; x*x?
No, again. The operation is to multiply ##x^2## and ##x^5##, which results in the exponents being added.pandaexpress said:Basically, you'd have a pair of x*x's five times. Or, you would get:
x*x*x*x*x; x*x*x*x*x Or, in other words, two groups of x*x*x*x*x.
It's the same idea with regular multiplication, where if you have 2X5, then it's like
|| || || || || (five groups of two) or |||||; ||||| (two groups of five)
I just don't quite understand why we're adding and getting 7 (instead of 10), since the operation is to multiply exponents.
Because the terms in ##x^2 + x^5## are not like terms (i.e., same exponent), they can't be combined.pandaexpress said:Do you guys see what I mean?
If they want you to add the exponents, then why not just say x2 + x5?
An exponent is a mathematical notation that indicates the number of times a number, called the base, should be multiplied by itself.
When multiplying numbers with the same base, the exponents are added because it represents repeated multiplication. For example, 23 * 24 is equivalent to 2 * 2 * 2 * 2 * 2 * 2 * 2, which is equal to 27.
When multiplying numbers with different exponents, you can apply the power rule. This means you can add the exponents if the bases are the same, or keep the base with the larger exponent and add the smaller exponent as a coefficient. For example, 23 * 25 = 28 and 26 * 32 = 26 * 9 = 182.
Yes, numbers with negative exponents can be multiplied. When a number has a negative exponent, it means it is in the denominator of a fraction. For example, 2-3 * 22 = 1/23 * 22 = 1/8.
Yes, there are a few exceptions to the rule of adding exponents when multiplying. For example, when multiplying powers with the same base but different exponents, if one of the exponents is 0, the product is equal to 1. In addition, when raising a power to another power, the exponents are multiplied. For example, (23)2 = 26.