Questions 5(b), 6(a), 7(a) and 4(c) (1 Viewer)

[azuill07]

can someone please post the answers to these questions thanks

 

[garry]

what's the question about?

 

[acmilan]

5(a)(i) t = 30 + 5(21-1) = 130 minutes

5(a)(ii)S = n/2[a + l] = 21/2[30+130]=1680 minutes = 28 hours

5(a)(iii)Refer to this thread for the answer
http://www.boredofstudies.org/community/showthread.php?t=46141&page=2

 

[acmilan]

6(a) let V = e^(x)

.'. V^2 +3V - 10 = 0

V = 2 or V = -5
e^(x) = 2 or e^(x) = - 5
x = ln 2 or x = no real solution
.'. x = ln 2

 

[acmilan]

7(a) (2^2) + (3^2) + (4^2) = 29


4(c)

y = 2secx
y^2 = 4sec^x

to get volume you integrate 4sec^2x from pi/3 to 0 and multiply the answer by pi

I think that will give you 4piroot3

 

[bevstarrunner]

5b)i) initial displacement x=4
ii) cos curve, amplitude 3, period pi, axis of symetry x=1 (ie, moved up 1)
iii) t= pi/2
iv) maximum speed when t=pi/4 OR t=3pi/4. Speed does not need direction so max speed x*=6

(correct me if i'm wrong..)

 

[acmilan]

Woops i thought you wanted 5(a), but you are right bevstarrunner