Science:Math Exam Resources/Courses/MATH152/April 2015/Question A 24
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Question A 24 |
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Write as a linear combination and or show it cannot be done. |
Make sure you understand the problem fully: What is the question asking you to do? Are there specific conditions or constraints that you should take note of? How will you know if your answer is correct from your work only? Can you rephrase the question in your own words in a way that makes sense to you? |
If you are stuck, check the hint below. Consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it! |
Hint |
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We want to find such that Try writing this vector equation as a system of linear equations and solving it using your favourite method. (The solution presented here will use row reduction.) |
Checking a solution serves two purposes: helping you if, after having used the hint, you still are stuck on the problem; or if you have solved the problem and would like to check your work.
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Solution |
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Found a typo? Is this solution unclear? Let us know here.
Please rate my easiness! It's quick and helps everyone guide their studies. We want to find such that We rewrite this vector equation as the augmented matrix of a linear system and apply row reduction: We introduce zeroes below the first pivot by adding appropriate multiples of the first row to the second and third rows (what are these multiples?): We then divide the second and third rows by -7 and -11, respectively: This is implies that ; substituting this into the first equation then yields . It follows that i.e., |