- #1

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(a)*I + (b)*J + (c)*K

You have to find a,b, and c. I know that I,J,&K are unit vectors and so I thought that a = 1, b = 0, c = 0. But the answer has radicals and fractions in it. I don't understand how to arrive at the solution.

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- Thread starter nando94
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- #1

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(a)*I + (b)*J + (c)*K

You have to find a,b, and c. I know that I,J,&K are unit vectors and so I thought that a = 1, b = 0, c = 0. But the answer has radicals and fractions in it. I don't understand how to arrive at the solution.

- #2

mfb

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Which background (which course) does the question have?

- #3

Mark44

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(a)*I + (b)*J + (c)*K

You have to find a,b, and c. I know that I,J,&K are unit vectors and so I thought that a = 1, b = 0, c = 0. But the answer has radicals and fractions in it. I don't understand how to arrive at the solution.

In terms of the unit vectors i, j, and k, <1, 0, 0> is 1i + 0j + 0k, or more simply, i. There shouldn't be any radicals or fractions.

- #4

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The problem gave a hint to do the dot product of the given vector with all the unit vectors. The previous problem was to express the vector <0,0,1> in terms of I,J&,K. The answer to that one was -sqrt(3)/2, 0,1/2. This one doesn't have answer in the back of the book and nothing in the chapter specifically talks about this problem.

- #5

HallsofIvy

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- #6

mfb

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Unless I,J,K have some special definition given somewhere, I don't see how the result could be different from the one that you calculated in post 1.

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That was my thought as well, that these represent some other set of unit vectors other than the canonical i, j, and k, and that nando94 did not specify what these I, J, and K are.Perhaps your "I", "J", and "K" (capital letters) mean something else?

nando94, what is the problem as written in the textbook, verbatim and in its entirety?

- #8

CompuChip

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But as said: we can keep guessing until you post more information, then we might be able to give you a conclusive answer.

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- #10

Mark44

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This is why we ask you to use the homework template, and post the complete problem statement. We were not able to read your mind that I, J, and K were given in the problem.The I,J,&K were vectors from a previous page that were supposed to be added together to result in <0,0,1>. I got the answer correct. Sorry for the confusion.

That may be, but it doesn't help if you don't provide all of the given information.This textbook is very unclear.

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