#logarithms y12

139 messages · Page 1 of 1 (latest)

novel relic
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hi what do i do, ik we equate but idk what to do after

abstract gust
novel relic
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what is the 3 x 2^x mean

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like is that basically saying 3 multiplied 2^x

abstract gust
novel relic
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so if i rewrite that

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hang on

abstract gust
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No need to re-write that

novel relic
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what do i do w the 15 and the 3

abstract gust
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Ok to make it easier to visualise let u=2^x

novel relic
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ignore the pencil but this is what i've got

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if this comes up on my mock i will kms 😭

abstract gust
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I think i just overcomplicated it

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Let u = 2^x

So we're just solving 3u = 15-2u

novel relic
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isnt the second term just 6^x

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since it's 3 x 2^x

abstract gust
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?

novel relic
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what

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oh

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the second bit of the equation aka the 3x2^x

abstract gust
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6^x = (3×2)^x not 3 × (2^x)

novel relic
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is that not just 6^x

abstract gust
novel relic
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how is that not 6^x

abstract gust
novel relic
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the way i see it

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it's 3 times 2^x

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which in my head is 6^x

abstract gust
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I think ur overcomplicating it

novel relic
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girl idk what i'm doing

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forgot abt logs so now i'm recapping it by doing ppqs

abstract gust
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Look

3×2^x = 15 - 2^(x+1)

3×2^x = 15 - 2×2^x

Instead of writing 2^x write u

3u=15-2u
5u=15
u=3

2^x = 3
x = log base 2 of 3

novel relic
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where the hell did the other 2 come from

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the 2nd line

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the second line of ur workings

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where did the other 2 come from 😭

abstract gust
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2^(x+1) = 2×2^x

novel relic
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what

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that doesn't make sense to me

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can u just do my mock paper atp 😭

abstract gust
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Raising something to the power of something is just repeated multiplication right?

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So 3^4 is just 3×3×3×3

novel relic
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no what

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when

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yeah

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i get that bit

abstract gust
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In the same way 2^(x+1) is the same is mutiplying 2 by itself x+1 times

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Right?

novel relic
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this line baffles me:

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i'm still genuinely so confused where the extra 2 from the rhs came from

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girl i was meant to start modelling with logs half an hour ago but i'm stuck on this

abstract gust
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Ok

2¹ × 2^x by laws of indicies the powers add so it equals 2^(x+1)

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Does that make sense

novel relic
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no..

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oh i see what u mean

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yeah

abstract gust
novel relic
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yep

abstract gust
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Oh ok u got it

novel relic
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but here the terms are different

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it's 3 and 2

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they're not the same so idk what to do

abstract gust
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The 3 and the 2 are like coefficients

novel relic
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kinda like how u can't do a^2 x b^3

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i mean

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u can to get a^2b^3

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but not like (ab)^5

abstract gust
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Multiplication is just repeated addition so if it makes it easier

3×2^x = 2^x + 2^x + 2^x

novel relic
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yeah so 2^x times that by 2^x times that by 2^x

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wait

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why are we

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nvm

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i'll go w the adding

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so that should surely be 6^x???

abstract gust
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Adding not multiplying

novel relic
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this is so fucking confusing bro i'm literally crying

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yeah that's still the same inni??

abstract gust
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So if i wrote

3x

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Then thats the same as x+x+x

novel relic
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if i were to multiply instead that would just be 8x^3

abstract gust
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Not x times x times x

abstract gust
novel relic
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multiplying 3 lots of 2^x

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wait wtf am i saying

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ignore that

abstract gust
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U can solve the equation 3x=15-2x right?

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Cuz this is the exact same

novel relic
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where did the extra 2 come from

novel relic
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i'm just like

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where did the extra 2 come from

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2x2^x is just 4^x

abstract gust
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I thought u said u understood that...

abstract gust
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Powers add

novel relic
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i understand the other bits after i just don't get that

abstract gust
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The base stays the same

novel relic
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yeah but

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oh

abstract gust
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Like gcse laws of indicies

novel relic
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so 2^1 * 2^x

abstract gust
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Yesss

novel relic
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that's just 2^x+1

abstract gust
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Yessss

novel relic
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what am i gonna take from there?? 😭

abstract gust
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Then u just rearrange to make 2^x the subject

novel relic
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huh

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they cancel out for me

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how come the extra 2 just disappears after

abstract gust
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What cancels out?

novel relic
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that's not how maths work

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the 2^x bit

abstract gust
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I swear if ur trolling

novel relic
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so we have to assign some sort of variable to it

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i swear i'm not

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i'm literally crying in a classroom over this question

abstract gust
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Oh ok

abstract gust
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Like u=2^x

novel relic
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holy shit why is the quality so bad

abstract gust
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Oh damn

novel relic
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i was meant to learn exponentials almost an hour ago but i'm stuck on this

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like wtf happens to it

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i'm just gonna pray this question doesn't come up on the mock

abstract gust
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?

regal forge
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$a * b^x + c * b^x = (a+c)b^x$

mystic hullBOT
regal forge
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The star is multiplication

clear relic
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$a\times b$

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🤔

mystic hullBOT
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clarence cant solve d1s

abstract gust
mystic hullBOT
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arizus

abstract gust
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🧠🧠