Saturday, 2 May 2009

Square Roots

What is the positive square root of 9? This was a question today (1st May) on the Weakest Link. So learn your maths and who knows, you could win a cash prize on TV. I hope that you know the answer to this question. It is three, but why did Ann Robinson ask for the positive square root? She asked because a positve number times a positive number is a positive number. This means that three time three is nine. There is another answer. A negative number times a negative number is a positive number. So if the question is 'what is the square root of 9' there are two answers, three and negative three.

Do you know the square root of zero? The answer is zero. If you multiply anything by zero you get zero, and this includes zero. we know we can get square roots of positive numbers and zero, but can we have a square root of a negative number? If we start with minus nine and look for the square root, we can't have three because 3 x 3 = 9. We can't have minus three because -3 x -3 = 9. I hope that everything in this blog has been simple for you because when you deal with square roots of negative numbers you have to use something called complex numbers, but that is the subject for another blog.

That sums it up

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