Mathematics
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OpenStudy (anonymous):
What is the average rate of change of the function f(x)= X^2-4x+7 on the interval 1
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OpenStudy (dumbcow):
basically its the slope formula:
f(3) -f(1)/ 3-1
OpenStudy (anonymous):
how did u get that?
OpenStudy (campbell_st):
find f(1) and f(3) average rate of change is
\[m = [(f(3) - f(1)]/(3 - 1)\]
OpenStudy (dumbcow):
rate of change = slope
technically avg rate of change is defined as:
\[\frac{1}{b-a}\int\limits_{a}^{b} f'(x) dx = \frac{f(b) -f(a)}{b-a}\]
OpenStudy (anonymous):
so can i use
m= Y2-Y1/X1-X2
?
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OpenStudy (dumbcow):
yep
the avg slope in that interval is the same as the slope of the line connecting the 2 endpoints
OpenStudy (anonymous):
0/2 ?
OpenStudy (dumbcow):
ok yeah thats it.
0/2 = 0
so the avg slope is 0
OpenStudy (anonymous):
g(x)=mx+b, x1<x<x2
OpenStudy (anonymous):
Without doing any calculation, how can one determine the average rote of change of g(x)= mx+b over the interval X1<X<X2 ?
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OpenStudy (dumbcow):
just plug it into the formula
g(x2)-g(x1)/ x2-x1
OpenStudy (anonymous):
and then ?
OpenStudy (anonymous):
finish?
OpenStudy (dumbcow):
simplify, you should find that things cancel
OpenStudy (anonymous):
mX2-mX1/X2-X1 ?
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OpenStudy (dumbcow):
yep, now factor out the m
OpenStudy (anonymous):
answer is m ?
OpenStudy (dumbcow):
yep :)
OpenStudy (anonymous):
If f(x)=1/3^x and g(x)=x^3, what is the domain of (f.g)(x)?
OpenStudy (anonymous):
(f into g)(x)
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OpenStudy (anonymous):
{x E R} ?
OpenStudy (dumbcow):
so you are plugging g(x) into the variable for f
--> 1/3^g(x) = 1/3^(x^3)
domain is all possible x_values
OpenStudy (anonymous):
(f.g)(x)
divided
OpenStudy (anonymous):
f(x).g(x)
OpenStudy (anonymous):
multiply
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OpenStudy (dumbcow):
??
OpenStudy (anonymous):
f(x) and g(x) are multiply
OpenStudy (dumbcow):
1/3^x * x^3
OpenStudy (anonymous):
yeah
OpenStudy (dumbcow):
thats it
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OpenStudy (anonymous):
what is the domain?
OpenStudy (dumbcow):
oh, all real num
there is no x value that makes it undefined
OpenStudy (anonymous):
{x E R} ?
x is not equal -1 ?
OpenStudy (dumbcow):
umm well R is used as notation for the set of all real numbers
OpenStudy (anonymous):
i mean x can't be equal -1 or x can't be equal 0 or x can't be equal 1 or
just { x E R } ?