Logarithms Watch

username2302349
Badges: 1
Rep:
?
#1
Report Thread starter 2 years ago
#1
Hi, I'm not sure how to answer this question.

If 2logan - loga (5n - 25) = loga4 find the value of n.

The answer and how to do it would be appreciated. Thanks!
0
quote
reply
wdkmwd
Badges: 3
Rep:
?
#2
Report 2 years ago
#2
As a Computer scientist I'll do my job and tag a person who should answer this easily

Zacken
2
quote
reply
oinkk
Badges: 3
Rep:
?
#3
Report 2 years ago
#3
Line 2: Raise the 2 up as a power of n.
Line 3: Use the subtraction law and divide both logs (since they are to the same base of a)
Line 4: Technically, you can raise both sides as a power of 'a', thus cancelling the a and the loga terms to leave a quadratic that you can solve. If that doesn't make sense, then you can just equate whatever is inside the brackets of the logs since they are to the same base of a.

Now it is just a quadratic to solve.

Any questions, give me a shout :-)

Name:  IMG_1659.JPG
Views: 94
Size:  387.8 KB
2
quote
reply
Zacken
Badges: 22
Rep:
?
#4
Report 2 years ago
#4
(Original post by oinkk)

Any questions, give me a shout :-)
Full solutions are against forum guidelines.
0
quote
reply
username2302349
Badges: 1
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by oinkk)
Line 2: Raise the 2 up as a power of n.
Line 3: Use the subtraction law and divide both logs (since they are to the same base of a)
Line 4: Technically, you can raise both sides as a power of 'a', thus cancelling the a and the loga terms to leave a quadratic that you can solve. If that doesn't make sense, then you can just equate whatever is inside the brackets of the logs since they are to the same base of a.

Now it is just a quadratic to solve.

Any questions, give me a shout :-)

Name:  IMG_1659.JPG
Views: 94
Size:  387.8 KB
Thank you so much!
0
quote
reply
oinkk
Badges: 3
Rep:
?
#6
Report 2 years ago
#6
(Original post by cassie05)
Thank you so much!
My pleasure!
0
quote
reply
wdkmwd
Badges: 3
Rep:
?
#7
Report 2 years ago
#7
(Original post by Zacken)
Full solutions are against forum guidelines.
Doesn't look like he cares mate.
2
quote
reply
morgan8002
Badges: 20
Rep:
?
#8
Report 2 years ago
#8
Figure out a way to get rid of the logs. Solve the resulting equation.
0
quote
reply
Student403
Badges: 18
Rep:
?
#9
Report 2 years ago
#9
(Original post by wdkmwd)
Doesn't look like he cares mate.
Which is a shame because full solutions don't help the OP as much as people think they do
0
quote
reply
wdkmwd
Badges: 3
Rep:
?
#10
Report 2 years ago
#10
(Original post by Student403)
Which is a shame because full solutions don't help the OP as much as people think they do


OP Got his answer, and i got my clever clogs badge.


Everyone's happy
0
quote
reply
Student403
Badges: 18
Rep:
?
#11
Report 2 years ago
#11
(Original post by wdkmwd)
OP Got his answer, and i got my clever clogs badge.


Everyone's happy
:facepalm:
0
quote
reply
thefatone
Badges: 3
Rep:
?
#12
Report 2 years ago
#12
(Original post by wdkmwd)
OP Got his answer, and i got my clever clogs badge.


Everyone's happy
derp not everyone...
(Original post by Student403)
:facepalm:
0
quote
reply
wdkmwd
Badges: 3
Rep:
?
#13
Report 2 years ago
#13
(Original post by Student403)
:facepalm:


:hello::hello:
0
quote
reply
wdkmwd
Badges: 3
Rep:
?
#14
Report 2 years ago
#14
(Original post by thefatone)
derp not everyone...




k.
0
quote
reply
ombtom
Badges: 16
Rep:
?
#15
Report 2 years ago
#15
(Original post by Student403)
Which is a shame because full solutions don't help the OP as much as people think they do
Maybe I'm just being weird again, but a full solution usually helps me a lot, because then I can work through it and see where I get stuck, and ask for help with that bit. And I can check if I've just made a simple mistake. I suppose everyone's different, and we need the "no full solutions" rule to benefit the majority.
1
quote
reply
Zacken
Badges: 22
Rep:
?
#16
Report 2 years ago
#16
(Original post by ombtom)
Maybe I'm just being weird again, but a full solution usually helps me a lot, because then I can work through it and see where I get stuck, and ask for help with that bit. And I can check if I've just made a simple mistake. I suppose everyone's different, and we need the "no full solutions" rule to benefit the majority.
You'd benefit more from being prodded along bit by bit, trust me - it really builds your mathematical ability. If you've made a simple mistake, then the best thing is for you to have posted your working and somebody else to just point that out for you. :-)
0
quote
reply
ombtom
Badges: 16
Rep:
?
#17
Report 2 years ago
#17
(Original post by Zacken)
If you've made a simple mistake, then the best thing is for you to have posted your working and somebody else to just point that out for you. :-)
True. :bigsmile:
0
quote
reply
Student403
Badges: 18
Rep:
?
#18
Report 2 years ago
#18
(Original post by ombtom)
Maybe I'm just being weird again, but a full solution usually helps me a lot, because then I can work through it and see where I get stuck, and ask for help with that bit. And I can check if I've just made a simple mistake. I suppose everyone's different, and we need the "no full solutions" rule to benefit the majority.
Imagine giving the OP "full solutions" as how people use the "Solution bank". You go to it when you're stuck and work through it and then you get it. The problem is Solution Banks aren't for everyone. You have to be very critical to be able to fully utilise it, because it will show you niche aspects of the question/solution that you might overlook. People often read a full solution and go "oh I'll get that in the exam" but this is definitely not the case all the time. This can be helpful but it's nowhere near as helpful as getting there yourself - writing the solution yourself.

It's sort of like the difference between theory and practical. In the former, you'll read it and it will definitely teach you something, but it's so easy to read over something that might have been a key aspect you'd have found out through your own experience, had you done the practical.

tl;dr full solutions can be helpful, but definitely not as much as getting there yourself

edit: to add, I can see the solution bank being useful for people like you because you're of the ability that you'll be much more likely to pick up the nitty gritty parts, but people on here are all different and rather than "assess" each one to determine if he/she is worthy of the straight solution, it helps everyone (some more than others) to be guided through the question instead
0
quote
reply
ombtom
Badges: 16
Rep:
?
#19
Report 2 years ago
#19
(Original post by Student403)
tl;dr full solutions can be helpful, but definitely not as much as getting there yourself

edit: to add, I can see the solution bank being useful for people like you because you're of the ability that you'll be much more likely to pick up the nitty gritty parts, but people on here are all different and rather than "assess" each one to determine if he/she is worthy of the straight solution, it helps everyone (some more than others) to be guided through the question instead
Talking of solution banks... Did you upload the M5 practise paper to that thread?
0
quote
reply
Student403
Badges: 18
Rep:
?
#20
Report 2 years ago
#20
(Original post by ombtom)
Talking of solution banks... Did you upload the M5 practise paper to that thread?
I didn't Find me the thread pl0x and I'll do it very soon
0
quote
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
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

University open days

  • University of Lincoln
    Mini Open Day at the Brayford Campus Undergraduate
    Wed, 19 Dec '18
  • University of East Anglia
    UEA Mini Open Day Undergraduate
    Fri, 4 Jan '19
  • Bournemouth University
    Undergraduate Mini Open Day Undergraduate
    Wed, 9 Jan '19

Were you ever put in isolation at school?

Yes (199)
27.95%
No (513)
72.05%

Watched Threads

View All