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Matrix Operations a la Shmoop you look at Gilligan Huffington III CEO of Handbags.com [man at white board]

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had a great earnings report in January and February with everyone feeling pretty good [doctors celebrating in meeting]

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about the bullish market and the economy doing better as a whole people are spending money

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like money is growing on trees finally being a great businessman that Gilligan is he wants [kid holding a fan of money]

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to project how well his company will do in March and April all together he estimates [man chases pig]

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that in March customers will probably buy half the amount of things they bought in January

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but they will will buy the same amount in April as they did in February here's out data

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for how many full price and discounted handbags watches and shoes he sold in January and February

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in matrix format why aren't we using tables? [matrices]

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well actually matrices are a good way to organize our data when we want to perform operations

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with them such as adding them or multiplying numbers to the data first lets figure out

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what the March and April data look like in March Gilligan estimates that customers will

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probably buy half the amount of things they bought in January so we can just take January's

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data and multiply the matrix by one half this is called multiplying by a scalar where scalar

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is just another name for a number in essence we will just multiply each number in the matrix

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by one half to get nine six five seven two and three those numbers are for Gilligan's

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purposes millions in April Gilligan estimates that the customers will buy the same amount

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in April as they did in February so we can just keep February's data the same Gilligan

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wants to find the total of March and April's data so we'll have to add the two matrices

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not that because the dimensions of both of these matrices are the same we can add them [teacher at white board in front of students]

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if they weren't we wouldn't be able to to add two matrices we can just add each corresponding

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pair of numbers we get nine plus eight equals seventeen six plus seven is thirteen five

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plus six is eleven seven plus two is nine two plus nine is eleven and three plus four

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is seven out final answer seventeen thirteen eleven nine eleven and seven looks like Gilligan's

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gonna have another great two months [money showering over man]

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