Question

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

Answer 1

@aum

negative pi over 16

negative 16 over pi

2 over pi

pi over two

Answer 2

use this formula
\(\huge \dfrac{f(b)-f(a)}{b-a}\)

Answer 3

basically you're finding the derivative, but over large interval, so we don't take limits.

you know how to find f(pi/2) and f(pi/4)
?

Answer 4

no nor really

Answer 5

im not that good with trig

Answer 6

to find f(pi/2), plug in x = pi/2 in f(x)

Answer 7

to find f(pi/4), plug in x = pi/4 in f(x)

Answer 8

ok

Answer 9

so a is pi/2?

Answer 10

and b is pi/4?

Answer 11

or the other way around?

Answer 12

doesn't matter :)

Answer 13

ok so pi/8?

Answer 14

pi/8 for what ?

Answer 15

wait no pi/2! right?

Answer 16

for the rate of change?

Answer 17

bc before its simplified, its 4pi/8!!! and then simplify

Answer 18

i foud the common denominator and ssimplifed

Answer 19

so you got pi/4 in the denominator, right ?

Answer 20

ok,

f(pi/2) = -5
f(pi/4) = -1

numerator = -5-(-1) = -4

so,
rate = -4/(pi/4) = -16/pi

Answer 21

no i got 4pi/8

Answer 22

thats incorrect
how u got that ?

Answer 23

common denominator by getting 8 and multiplying each by 4 and 2

Answer 24

or would you hve to go to 16?

Answer 25

8

so,