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The Power of 1. Debbie Poss Lassiter High School Deborah.poss@cobbk12.org. One Person’s Question…. What is the value of. One Person’s Question…. Should we teach PEMA ?. The Power of 1. “One is the Loneliest Number” “One More Day” “We are #1!”. The Power of 1.
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The Power of 1 Debbie Poss Lassiter High School Deborah.poss@cobbk12.org
One Person’s Question… • What is the value of
One Person’s Question… • Should we teach PEMA ?
The Power of 1 • “One is the Loneliest Number” • “One More Day” • “We are #1!”
The Power of 1 • Smallest Natural Number • Greeks didn’t consider it a number at all.
The Power of 1 • So 1 is not prime because it doesn’t have 2 natural number factors.
The Power of 1 • Euclid thought 1 was powerful because it guaranteed an infinite number of primes…
The Power of 1 • Let m and n be 1st two primes. • Consider mn + 1 • Can it be factored? • Then mn + 1 is also prime. • Let m, n and p be 1st three primes… • Consider mnp + 1…
The Power of 1 • Important in our language, though… • Unit • Unique • Unity • Universal • All based on Latin word for 1.
The Power of 1 • Multiplicative Identity • kX1 = 1Xk = k for all k
The Power of 1 • Understood (or Misunderstood) 1 • A + 3A = 4A
The Power of 1 • 1 is the only integer that always produces more by addition than by multiplication. • (I + k > k but 2 + k > 2k isn’t always true.)
1 as a Power • n1=n • POWERFUL!
The Power of 1 Most students see that 9n∙9m=9n+m • So 91/2 ∙ 91/2=91 • Two equal numbers whose product is 9…
1 as a Power Therefore
1 as a Power • And • So
The Powers of 1 • 1x=1 for all x. • 0 can’t be raised to negative powers • -1 raised to even powers isn’t equal to -1
The Powers of 1 • 11/2= 1 which means • However, there are two square roots of 1. The principle square root is 1, but the other square root is -1, because both numbers satisfy the equation x2=1.
The Fourth Roots of 1 • Solving x4 = 1 can be done intuitively. • x = 1 or x = -1 • x = i or x = -i
The Third Roots of 1 • Since x3 = 1 is cubic, there are 3 cube roots of 1 and we can find them all.
The Powers of 1 • Let’s graph these roots in the complex number plane… imaginary 2 1 -1 -2 real -3 -2 -1 0 1 2 3 4
imaginary (cos θ , sin θ) 1 θ real
The Powers of 1 Think about it. What is the sum of the 5 fifth roots of unity (i.e. The 5 fifth roots of 1)?
The Powers of 1 ARML Question: Find the sum of the four non-real fifth roots of 1. • -1
Find all 6 sixth roots of 1. Obviously 1 and -1. The angle between roots is 360°/6 = 60° cos 60° + isin 60 ° =
Find all 6 sixth roots of 1. And by using the symmetry of the graph…
Reflect Upon the Power of 1 • Is there 1 person who inspired your love for mathematics? • Is there 1 person who inspired you to be a mathematics teacher? • Is there 1 person who helped you be the person you are today?
Reflect Upon the Power of 1 • To the world you may be just one person, • But to one person, you may be the world. -Brandi Snyder
Reflect Upon the Power of 1 • Go out and have ….“One Fine Day”