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What is the additive inverse of 9.1?
We are talking group theory here. A group with addition has an additive inverse. A group with multiplication has a multiplicative inverse. The additive inverse of a number x is a y with x + y = 0. The additive inverse of x is written -x. Hence, the additive inverse of 9.1 equals -9.1. The reason that this question can arise is that beyond groups, there are rings and fields. Rings and fields have, besides addition, also multiplication. An element can have an additive inverse and a multiplicative inverse at the same time.
Is distance traveled versus time at a constant speed a direct or inverse porportion?
Think about it. If you travel for more time, would you advance a greater distance (that would be a direct proportion), or less distance (that would be an inverse proportion)?
Does a constant of proportionality exist?
Yes, it does. Every time there are variables in direct or inverse relationship, there is a constant of proportionality.
Why when multiplying two negative numbers do you get a positive number?
The answer has to do with the fundamental properties of operations on numbers (the notions of "addition", "subtraction", "multiplication", and "division"). Each number has an "additive inverse" associated to it (a sort of "opposite" number), which when added to the original number gives zero. This is in fact the reason why the negative numbers were introduced: so that each positive number would have an additive inverse. For example, the inverse of 3 is -3, and the inverse of -3 is 3. Note that when you take the inverse of an inverse you get the same number back again: "-(-3)" means "the inverse of -3", which is 3 (because 3 is the number which, when added to -3, gives zero). To put it another way, if you change sign twice, you get back to the original sign. Now, any time you change the sign of one of the factors in a product, you change the sign of the product: (-something) × (something else) is the inverse of (something) × (something else), because when you add them (and use the fact that multiplication needs to distribute over addition), you get zero. For example, (-3) ´ (-4) is the inverse of (3) ´ (-4) because when you add them and use the distributive law, you get . (-3) ´ (-4) + (3) ´ (-4) = (-3 + 3) ´ (-4) = 0 ´ (-4) = 0 So (-3) ´ (-4) is the inverse of (3) ´ (-4) , which is itself (by similar reasoning) the inverse of 3 ´ 7. Therefore, (-3) ´ (-4) is the inverse of the inverse; in other words, the inverse of -12 in other words, 12. The fact that the product of two negatives is a positive is therefore related to the fact that the inverse of the inverse of a positive number is that positive number back again.
What is an inverse proportion?
Two variables are said to be in inverse proportion if their product is a constant.So, if X and Y are in inverse proportion, thenXY = k or Y = k/X for some constant k.If you double X then Y is halved. If you decrease X by a factor of 3 then Y is trebled.A common example is Speed and Time for covering a fixed Distance.
