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 April 22nd, 2011, 09:28 PM #1 Newbie   Joined: Apr 2011 Posts: 1 Thanks: 0 Some advanced precalculus questions I got a bunch of homework. But these are the hardest. Others I could have some clues to solve, but for these I'm clueless. Please help 1) If f(x)=3sin x+4sin(x-3) what is the amplitude and period (p) of f(x)? A) a= 1.114, p = 6.283 B) a= 1.114, p = 3.141 C) a =2.28, p= 3.141 D) a=7, p = 6.283 E) a= 7, p= 9.425 2)A Ferris wheel rider's height above the ground is given by the function h(t)= 20+18 cos [ (pi/4)* (t-3)], where h is measured in feet and t in seconds. How much time is required for the Ferris wheel to complete 1 full revolution? A) 3 secs B) 8 secs C) 18 secs D) 20 secs E) 38 secs 3) The graph of the daily temperature at noon of a city is modeled by T= -25 cos [ (2pi/365) * (t-30)] +70, where T represents the temperature in degrees Fareinheit and t represents the day of 365- day year. Whats the range of the temperature from low to high during the year? A) 25-> 70 Celsius B) 30-95 Celsius c) 45-95 Celsius D) 30-90 Celsius E) 35-95 Celsius 4) If f(x)= sin x* sin (-x), then which is the range of f(x)? A) [0,1] B) [-1,0] C) [-1,1] D) [-1,0) E) (0,1] 5) Function D (t) = (4t)/ (0.01t square+5.1). Given the concentration, D, of a drug in bloodstream where D is measured in micrograms per milliliter and t is minutes from the time the drug is taken. What's the maximum concentration of the drug found in bloodstream at any time? A) 0.01 micrograms/ milliliters B) 4 micrograms/ milliliters C) 5.1 micrograms/ milliliters D) 8.856 micrograms/ milliliters E) 22.583 micrograms/ milliliters April 23rd, 2011, 04:36 AM #2 Senior Member   Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 521 Math Focus: Calculus/ODEs Re: Some advanced precalculus questions 1.) We may use the identity Thus, amplitude is Period is 2.) The period is 3.) The range in degrees Fahrenheit is 4.) range is [-1,0] 5.) Graphing shows D is the only answer which makes sense. I would use a technique from calculus to find the maximum is . April 23rd, 2011, 04:52 AM   #3
Math Team

Joined: Dec 2006
From: Lexington, MA

Posts: 3,267
Thanks: 408

Re: Some advanced precalculus questions

Hello, belly!

Quote:
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MarkFL "eyeballed" the problem! . . . Great1
[color=beige] .[/color] April 23rd, 2011, 05:31 AM   #4
Math Team

Joined: Dec 2006
From: Lexington, MA

Posts: 3,267
Thanks: 408

Re: Some advanced precalculus questions

Hello again, belly!

Quote:
 [color=beige]. . [/color] [color=beige]. . [/color]

Since this is [color=blue]pre[/color]-Calculus, MarkFL has the best approach . . . graphing.

If we are allowed to use Calculus, we can directly determine the maximum concentration. Tags advanced, precalculus, questions ,

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difficult question for precalculus

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