Warm-Up: January 30, 2013

Warm-Up: January 30, 2013 • Evaluate each expression for x=2 • x5 • 5x • 5-x

Due: Page 358 #15-24, 26, 30, 36-41 16) 1.09 18) 0.98 20) 0.918 22) 1.0008 24) 32 26) 1024 30) 8100 36) a) 440 b) 1760 38) a) 132 b) 135,168 40) a) 675 b) 6075

Homework Questions?

Warm-Up: January 31, 2013 • A biologist places 100 bacteria in a petri dish. An hour later, there are 175 bacteria in the petri dish. • 1) What was the increase in bacteria? • 2) What is the growth rate of bacteria? • 3) How many bacteria would there be 24 hours after the biologist placed the first 100 bacteria into the petri dish?

Exponential Functions Section 6.2

Essential Question • Given a function, how can we tell if it is exponential growth, exponential decay, or not exponential?

Exponential Function • Exponential Function: A function of the form f(x)=bxwhere the base, b, is a positive real number other than one.

Example 1: Identify each as linear, quadratic, or exponential • f(x) = 3x-9 • g(x) = (x-3)(x+1) • h(x) = x(2-x) • j(x) = 3x – 24 • k(x) = 123x

Growth vs. Decay for f(x)=a(b)x, a>0 • Exponential growth: b>1 and x>0 • Exponential decay: 0<b<1 and x>0 • If there is a negative in the exponent, take the reciprocal of b prior to testing for growth/decay.

Example 2: Growth or Decay?

Assignment • Page 367 #10-24 ALL

Classwork Answers 10) linear 11) quadratic 12) exponential 13) exponential 14) exponential 15) quadratic • 16) growth • 17) growth • 18) decay • 19) decay • 20) decay • 21) decay • 22) decay • 23) decay • 24) decay

Warm-Up: January 30, 2013