Question

What is the rate of change for f(x) = −2 cos 4x − 3 on the interval from x=pi/4 to x=pi/2?

Answer 1

@undeadknight26 can you help?

Answer 2

o.o
this stuff is some really advanced stuff i have not learned yet...sorry mate! @whpalmer4 @iPwnBunnies @surjithayer @hba @Lena772 @Compassionate @mathslover

Answer 3

ok, thank you

Answer 4

what is the slope of the line between the endpoints of the stated interval?

Answer 5

for some interval [a,b], the slope between the endpoints is just:

\[\frac{f(b)-f(a)}{b-a}\]

Answer 6

That is all the information we were given.

Answer 7

then use it :)

Answer 8

they give you a,b, and f(x) .... thats all we need right?

Answer 9

I am so confused with this stuff. I'm in Algebra 2, which I was doing pretty good with, but then the last chapter is trig and I just don't get it.

Answer 10

do you know how to input a value into a function?

Answer 11

Do I have to graph it first?

Answer 12

yes

Answer 13

'have to'? no .... it you want to sure ... but all we need is values

Answer 14

then they gave you f(x),

what is f(pi/4)?
what is f(pi/2)?
what is (pi/4 - pi/2)?

Answer 15

f(x) = -2cos(4x) - 3

f(pi/4) = -2cos(4pi/4) - 3

f(pi/4) = -2cos(pi) - 3

f(pi/4) = -2(-1) - 3 ...
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f(x) = -2cos(4x) - 3

f(pi/2) = -2cos(4pi/2) - 3

f(pi/2) = -2cos(2pi) - 3

f(pi/2) = -2(1) - 3

Answer 16

had the interval going the wrong way but its:

(pi/2 - pi/4) = pi/4

Answer 17

f(pi/4)=(0,pi/4)

Answer 18

f(pi/4) is not a point ... especcially not a point where x=0 and y=pi/4, since x=pi/4

Answer 19

f(pi/2)=(0,pi/2)

Answer 20

Those are the y intercepts

Answer 21

why in the world would you be trying to assess any y intercepts?

Answer 22

I want to find the slope then?

Answer 23

the y intercept of a function doesnt change based upon the value of x that you use ....

the only x value for a y intercept is x=0: f(0) gives the y intercept value

Answer 24

you want to find the slope between: f(pi/2) and f(pi/4) yes