9th Grade Math Help on Polynomials

[Lilly855678]

[h=1]9th Grade Math Help (PLEASE Help Me!!)[/h]I need ASAP help on how to just set up these problems... what they mean and all that; I'm not just looking for the answer. The first one goes like this:

The equation P=0.00267sF gives the power P (in horsepower) needed to keep a certain bicycle moving at speed s (in miles per hour), where F is the force of road and air resistance (in pounds). On level ground this force is given by F=0.0116s²+0.789. Write a polynomial function (in terms of s only) for the power needed to keep the bicycle moving at speed s on level ground. How much power does a cyclist need to exert to keep the bicycle moving at 10 miles per hour?
What I got was: The power needed to maintain a speed of s is .00267s(.0116²+.789), so the power needed to maintain a speed of 10 mph would be .0520383. Is this even close to right??

The second one is this:

For 1980 through 1995, the number of degrees D (in thousands) earned by people in the United States and the percent of degrees P earned by women can be modeled by
D= -0.096t⁴+3t³-27t²+91t+1700
P= 0.43t+49
where t is the number of years since 1980. Find a model that represents the number of degrees W (in thousands) earned by women from 1980 to 1995. How many degrees were earned by women in 1991?
I haven't even tried this one yet... I have no idea at all what it means I'm so confused!!

Please, please, PLEASE help me I'm so confused and on the verge of tears because I'm scared that I might get a really bad grade on the quiz tomorrow... please help me I'm begging you I'm so confused right now

 

[stapel]

I need ASAP help on how to just set up these problems... what they mean and all that.... I might get a really bad grade on the quiz tomorrow.

Did the instructor not cover this material at all in class? (How else would students not even know what the terms mean, etc, right?) You might want to have a serious talk with your academic advisor. You should not be tested over material which was never mentioned in class. :shock:

The equation P=0.00267sF gives the power P (in horsepower) needed to keep a certain bicycle moving at speed s (in miles per hour), where F is the force of road and air resistance (in pounds). On level ground this force is given by F=0.0116s²+0.789. Write a polynomial function (in terms of s only) for the power needed to keep the bicycle moving at speed s on level ground. How much power does a cyclist need to exert to keep the bicycle moving at 10 miles per hour?

What I got was: The power needed to maintain a speed of s is .00267s(.01162+.789)....

Why did you remove the variable from the "force" expression? Why did you not then simplify the addition inside the parentheses? What was your reasoning?

For 1980 through 1995, the number of degrees D (in thousands) earned by people in the United States and the percent of degrees P earned by women can be modeled by
D= -0.096t4+3t3-27t2+91t+1700
P= 0.43t+49
where t is the number of years since 1980. Find a model that represents the number of degrees W (in thousands) earned by women from 1980 to 1995. How many degrees were earned by women in 1991?

I haven't even tried this one yet... I have no idea at all what it means

The exercise is giving you formulas that provide numbers which measure certain things over certain periods of time.

"For 1980 through 1995": This gives you the years during with the formulas are "good". These are years, being 1980, 1981, 1982, ..., 1994, and 1995, during which the formulas give the correct values for the values being measured.

"the number of degrees D (in thousands) earned by people in the United States": This is defining the variable, D, and saying for what it stands. D stands for the number of thousands of university degrees (such as bachelors degrees and masters degrees) which people received from four-year universities. For instance, "D = 2" means "2*1000 = 2,000 degrees"; "D = 3.4" means "3.4*1000 = 3,400 degreees"; and so forth.

"and the percent of degrees P earned by women": This is defining the variable, P, and saying for what it stands. P stands for the percentage of the degrees (given by D) which were earned by women. For instance, "P = 52" means "52% of the degrees were awarded to women".

"can be modeled by": This is saying that the formulas which follow give good (though perhaps approximate) values for the numbers of degrees awarded to students in a given year and the percentages of those degrees earned by women.

"where t is the number of years since 1980.": This is defining the variable, t, and saying for what it stands. t stands for the number of years since 1980, when the models enter their interval of validity. For instance, "t = 0" means "in the year 1980"; "t = 5" means "in the year 1985"; and so forth.

"Find a model": This is asking you to create an equation which provides good values for something that is being measured.

"that represents the number of degrees W (in thousands) earned by women": This is defining the variable, W, and saying for what it stands. W stands for the number (rather than the percentage) of degrees which were awarded to women in a given year t.

"from 1980 to 1995": This tells you the time interval for your model. This also lets you know that you can use the modeling formulas they've already given you, since the periods of validity are the same.

"How many degrees were earned by women in 1991?": This is asking you to use the model you create in the previous step, and evaluate it at the appropriate value of t.

So ask yourself: Given an absolute number which is the total of two or more subgroups, and given a percentage of that total number which stands for the absolute number of a particular subgroup, how would one find the absolute number of that particular subgroup?

To learn how to set up and solve "percent of" word problems, try here.