Question

Calculus help? Please check my work?

A spring is moving up and down according to the function s(t) = -4cos(t).
Part a) Find the first derivative and calculate the velocity of the spring at t =3 pi/4
Part b) Is the spring moving upward or downward at this point? Justify your answer

Answer 1

Where is your work to check?

Answer 2

v=4sint

Answer 3

(+) up (-) down

Answer 4

@CGGURUMANJUNATH 4sin t?

Answer 5

now put t=3(pi/4)

Answer 6

That's the derivative

Answer 7

I thought the derivative of the first function was 0

Answer 8

how zero ;can u show ur steps @VIbarguen1

Answer 9

it is not zero.

Answer 10

@VIbarguen1 use the product rule , u r right 0 , do second part of product rule

Answer 11

no wait you are right. I'm sorry

Answer 12

Yeah I did the product rule but didn't finish

Answer 13

Sinx=cosx , cosx=-sinx

Answer 14

so now I insert 3(pi/4)

Answer 15

yes

Answer 16

that would be 1/sqrt 2 right?

Answer 17

4*sin(135)

Answer 18

(3*pi)/4=135 degrees

Answer 19

right so 4* sin (135) = 2/sqrt 2

Answer 20

4*sin(135)=2.82

Answer 21

ok right sorry. Yeah I have to turn it to decimal

Answer 22

so th espring is moving upward because it is positive right?

Answer 23

yes

Answer 24

Yup, u got it

Answer 25

Thank you!!

Answer 26

:)