Question

list all x intercepts for y=-3cos(4x+pi/3) on the interval [-pi/6,pi/2]

Answer 1

to find x-intercepts, put y=0;
so u get -3cos(4x+pi/3)=0
=>4x+pi/3=npi/2 , wer n=1,3,5....
but we hav
-pi/6<(2m+1)pi/2<pi/2 (equality is also there)
=> m=0 is the only solution and hence 4x+pi/3=pi/2
=> x=pi/24

Answer 2

i dont get that

Answer 3

also that is nt one of the answers
could it be the range?

Answer 4

as in ? post the answer options please ?

Answer 5

a)( pi/24, 7pi/24)

Answer 6

b(pi/4, pi/24)

Answer 7

c)-pi/12, 5pi/12

Answer 8

d)( pi/12, 5pi/24)

Answer 9

e)( 0, 7pi/24)

Answer 10

cos is zero at either 2pi or pi

Answer 11

oops its zer0 @ pi/2 or -pi/2

Answer 12

ok

Answer 13

deos that chaneg your answer?

Answer 14

nope...answer is pi/24 and 7pi/24
option is A.

Answer 15

gotcha, thanks a ton!

Answer 16

done :)

Answer 17

does that mean you were solving for the locations of pi/2 and -pi/2?

Answer 18

no no...i was solving for pi/2 and 3pi/2. solving for -pi/2 is also coreect ,but just that the x value u get doesn't not lie in the given domain :)

Answer 19

ok, gotcha. you were solving for Pi/2 and 3pi/2 because that is where cos = 0 - correct?

Answer 20

exactly!

Answer 21

it;'s been over a decade so I am very very rusty - appreciate your help !