Math Is Fun Forum

belly

Member

Registered: 2011-04-22

Posts: 1

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

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Some advanced precalculus questions

Hi belly;

For #3 I am getting 95F and 45F, I do not see that in your choices of celsius. Have you copied the question correctly?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Some advanced precalculus questions

Hi belly,

1)

Last edited by gAr (2011-04-22 19:04:51)

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Some advanced precalculus questions

2)

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Some advanced precalculus questions

3)
45-95 Fahrenheit,

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Some advanced precalculus questions

4)

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Some advanced precalculus questions

5)

Thought of differentiation, but since you say it's pre-calculus question, here's a method of substitution.

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."