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Warmup Alg 2 16 Feb 2012. Warmup Alg 2 17 & 21 Feb 2012. Agenda. Don't forget about resources on mrwaddell.net Sec 7.4: Intro to logarithms Definition of logs Inverses of logs. Go over assignment from last class period. Section 7.4: Introduction to Logarithms. Vocabulary.
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Agenda • Don't forget about resources on mrwaddell.net • Sec 7.4: Intro to logarithms • Definition of logs • Inverses of logs
Vocabulary • Exponentials • Logarithm Any equationof the form y=(b)x The opposite of an exponential equation Logby=x y=bx if and only if
A different look • BASEEXPONENT = POWER (exponential) • 42 = 16 • 4 is the base. 2 is the exponent. • 16 is the power. • As a logarithm, logBASEPOWER=EXPONENT • log 4 16 = 2
Examples • Write the following in log or exponential form: • 27 = 128 • log6 1296 = 4 • 3= log7 343 • 35 = 243 log2 128 = 7 64 = 1296 73 = 343 log3 243 = 5
Property of Logs and Exponents • One-to-One Property of Exponential Functions • If bx= by, thenx = y.
Inverse Properties (2 of them) logbbx = x log228= 8 5
Finding Inverses of functions • y=log7x Using the definition of an inverse, becomes: Switch the x and y’s, solve for y x=log7y Bcs of the def. of log & exponents y=7x
Finding Inverses of functions • y=3x Using the definition of an inverse, becomes: Switch the x and y’s, solve for y x=3y Bcs of the def. of log & exponents y=log3x
Assignment • Chapter 7.4: pg 503: • 8-19, • 28-33, • 37-41