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Warm-Up. 1) Write in exponential form. 2) Write in logarithmic form. log 27 9 = x. 5 x = 2003. 3) Evaluate. 4) Write the Equation that models this situation:
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Warm-Up 1) Write in exponential form. 2) Write in logarithmic form. log279 = x 5x = 2003 3) Evaluate. 4) Write the Equation that models this situation: The current world population of Oompa-loompas is 7,986. If the Ooompa-loompa population grows steadily at a rate of 19% per year, what will their total population be in 10 years?
Properties of Logarithms loga1 = 0 because a0 = 1 logaa = 1 because a1 = a logaax = x If loga x= loga y then x =y Product Property Quotient Property Power Property Change-of-Base
Remember Common Logarithm?? log10 Is the “common” logarithm This is the LOG button on the calculator Sometimes we’re lazy and we don’t even write the base… log107 = log 7
Basic Properties of Logarithms 1) loga1 = 0 because a0 = 1 2) logaa = 1 because a1 = a
3) One-to-one Property: If loga x = loga y then x=y
Product Property Express as a sum of logarithms. 1) loga MN = loga M + loga N 2) logb AT = logb A + logb T 3) log MATH = log M + log A + log T + log H
Ex. Express as a single logarithm 4) log5 19 + log5 3 = log5 (19*3) 5) log C + log A + log B + log I + log N = log CABIN
Ex. Express as a sum of logarithms, then simplify 6) log2 (4*16) = log2 4 + log216 = 2 + 4 = 6
Ex. 7 Use log53 = 0.683 and log57 = 1.209 to approximate… log5 (21) = log5 (3*7) = log5 3 + log5 7 = 0.683 + 1.209 = 1.892
1) Ex. Express as the difference of logs 2)
Ex. 3 Use log53 = 0.683 and log57 = 1.209 to approximate… = log5 3 - log5 7 = 0.683 - 1.209 = -0.526
try these: conclusions...
Ex. Express as a product. = -5 * logb9 4) 5)
Ex. 6 Use log53 = 0.683 and log57 = 1.209 to approximate… log5 49 = log5 72 = 2 log5 7 = 2(1.209) = 2.418
Ex. 7 Expand. log105x3y log105 + log10x3 + log10y log105 + 3 log10x + log10y
Ex. 8 Expand • Simplify the division. • Simplify the multiplication of 4 • Change the radical sign to an exponent • Express the exponent as a product
Ex. Condense. 9) 10)
Ex 11 Condense • Express all products as exponents • Change the fractional exponent to a radical sign. • Simplify the subtraction. • Simplify the addition.
Change-of-Base this allows us to change from any base to base 10
Ex. 1 Evaluate. Round to four decimal places. = 1.7712 Be careful about the parenthesis in the calculator… log(7) / log(3)
Ex. 2 Evaluate. Round to four decimal places. = 0.2626