C3 maximum of graph question

Watch this thread
BananaBanana101
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 6 years ago
#1
Can someone please explain to me why the answer to (b) (I) is 4/12-10
I feel like I don't fully understand how to calculate the maximum and minimum of a graph

Thank you
0
reply
BananaBanana101
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report Thread starter 6 years ago
#2
(Original post by BananaBanana101)
Can someone please explain to me why the answer to (b) (I) is 4/12-10
I feel like I don't fully understand how to calculate the maximum and minimum of a graph

Thank you

Question:
Attached files
0
reply
Covington4
Badges: 19
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 6 years ago
#3
(Original post by BananaBanana101)
Can someone please explain to me why the answer to (b) (I) is 4/12-10
I feel like I don't fully understand how to calculate the maximum and minimum of a graph

Thank you
Pretty sure you have to use your answer to part a, what did you get for that part?

Posted from TSR Mobile
1
reply
BananaBanana101
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report Thread starter 6 years ago
#4
(Original post by Ben4)
Pretty sure you have to use your answer to part a, what did you get for that part?

Posted from TSR Mobile

10cos(theta - 0.927)

(Correct)
0
reply
testing1234568
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report 6 years ago
#5
(Original post by BananaBanana101)
10cos(theta - 0.927)
So you can write:
P(theta) = 4/(12-10cos(theta-0.927))

Since this is always positive, you know that P is a maximum when the denominator ( 12 - 10cos(theta-0.927) ) on the right is as small as possible.

Can you think what the smallest value of 12 - 10cos(theta-0.927) is and when it occurs?
0
reply
BananaBanana101
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report Thread starter 6 years ago
#6
(Original post by studentro)
So you can write:
P(theta) = 4/(12-10cos(theta-0.927))

Since this is always positive, you know that P is a maximum when the denominator ( 12 - 10cos(theta-0.927) ) on the right is as small as possible.

Can you think what the smallest value of 12 - 10cos(theta-0.927) is and when it occurs?
So inverse cos -1 = pie add 0.927

Out of curiosity why am I allowed to do -10cos(theta - 0.927)

Thank you!
0
reply
testing1234568
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 6 years ago
#7
(Original post by BananaBanana101)
So inverse cos -1 = pie add 0.927

Out of curiosity why am I allowed to do -10cos(theta - 0.927)

Thank you!
Sorry, I misread. The denominator is 12+10cos(theta-0.927).
Find the minimum value this takes and the value of theta at which it occurs.
0
reply
BananaBanana101
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report Thread starter 6 years ago
#8
(Original post by studentro)
Sorry, I misread. The denominator is 12+10cos(theta-0.927).
Find the minimum value this takes and the value of theta at which it occurs.
No what you said is correct to the mark scheme!
0
reply
testing1234568
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
Report 6 years ago
#9
(Original post by BananaBanana101)
No what you said is correct to the mark scheme!
What I said would get you the correct minimum value of P but an incorrect value of theta (unless you made a mistake that cancelled out mine! xD)
0
reply
Snasher350
Badges: 5
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#10
Report 6 years ago
#10
(Original post by BananaBanana101)
Question:
Can you explain part (a) of the question please
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Has advance information helped during your exams?

Yes (62)
65.96%
No (25)
26.6%
I didn't use it to prepare (7)
7.45%

Watched Threads

View All
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise