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A pupil is beaten badly by this G.P.

One of my cocky students (wants to do medicine because maths is too easy) asked to give him my "best shot" because there was no question on G.P.s he could not do...

So I made this question, live at his lesson, and he was beaten really badly.
Non Calculator As Well.

Any thoughts?

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Reply 1

TSRforum

Should have given him this:
U1 + U2 = 150
U2 + U4 = -75

Find a and r

Posted from TSR Mobile

Reply 2

TSRforum

Help me in the C4 d.e. thread please 🙃

Posted from TSR Mobile

Reply 3

TeeEm

Original post by TSRforum

Should have given him this:
U1 + U2 = 150
U2 + U4 = -75

Find a and r

Posted from TSR Mobile

he managed this type ...

Reply 4

The.Joker

The title of the thread led me to believe a kid got beaten up by his doctor...

Reply 5

TSRforum

Also I'm pretty sure doing maths is harder than medicine, is it?

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Reply 6

TeeEm

Original post by TSRforum

Also I'm pretty sure doing maths is harder than medicine, is it?

Posted from TSR Mobile

I think it might be ...

Reply 7

the bear

Original post by TeeEm

Any thoughts?

all his base are yours

:nyan:

Reply 8

Zacken

Original post by TeeEm

Any thoughts?

\displaystyle \frac{u_1}{1-r} = 4u_1 r

(sum to infinity is four times as big as second term), hence, since

u_1 \neq 0

\displaystyle 4r^2 - 4r + 1 = 0 \iff r = \frac{1}{2}

, now we know that the sum to infinity is 192, so:

\displaystyle 2u_1 = 192 \iff u_1 = 96

. So, the sum to

k

terms is:

\displaystyle \frac{96(1-2^{-k})}{2^{-1}} = 180 \iff 2^{-k} = 2^{-4} \iff k = 4

(edited 8 years ago)

Reply 9

TeeEm

Original post by the bear

all his base are yours

:nyan:

had to be done...

Reply 10

TeeEm

Original post by Zacken

\displaystyle \frac{u_1}{1-r} = 4ar

(sum to infinity is four times as big as second term), hence, since

a \neq 0

\displaystyle 4r^2 - 4r + 1 = 0 \iff r = \frac{1}{2}

, now we know that the sum to infinity is 192, so:

\displaystyle 2u_1 = 192 \iff u_1 = 96

. So, the sum to

k

terms is:

\displaystyle \frac{96(1-2^{-k})}{2^{-1}} = 180 \iff 2^{-k} = 2^{-4} \iff k = 4

you win the "Brucie" bonus ...!!

Reply 11

Zacken

Original post by TeeEm

you win the "Brucie" bonus ...!!

Is that correct? Yay. Can you see my face yet? :tongue:

Reply 12

TeeEm

Original post by Zacken

Is that correct? Yay. Can you see my face yet? :tongue:

I cannot see your face ... Don't you have a better picture?!

Reply 13

Zacken

Original post by TeeEm

I cannot see your face ... Don't you have a better picture?!

Blame monobrow girl: @tinkerbella~

Reply 14

TeeEm

Original post by Zacken

Blame monobrow girl: @tinkerbella~

has she dented your confidence?

Reply 15

tinkerbella~

Original post by TeeEm

has she dented your confidence?

I have a great picture of his face if you want to see it :yep:

Reply 16

TeeEm

Original post by tinkerbella~

I have a great picture of his face if you want to see it :yep:

I would love to

Reply 17

Student403

Original post by Zacken

Yours looks much neater but hey - I've never attempted one of TeeEm's before so let me have my moment :wink:

Spoiler

Reply 18

Zacken

Original post by Student403

...

Nice work!

Reply 19

tinkerbella~

Original post by TeeEm

I would love to

He sent me nasty threats and I'm too scared.
Btw I thought this thread was going to be some big NHS scandal but it's just maths, the disappointment hurts.