Number 7 . Doubt

[uncut parrot]

I used the b²-4ac ≥0 inequality.
I came to that last inequality
Summation of ak² ≥ square of summation of ak /4 k from 1 to n .
Now I don't know how to proceed further to find values of n.

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[dim forge]

the nostalgia

[dim forge]

Try some values for a_k. For example, what if all the ak were equal to some nonzero constant C? you'd have nC^2 >= n^2C^2/4 giving us n =< 4.

For smaller n, use cauchy Schwarz

[humble burrow]

Do they teach Cauchy Schwartz in comp math?

[dim forge]

yes, extremely early on too

[humble burrow]

Makes sense, I guess they love the inequalities.

RA flashbacks

[dim forge]

eitherways this doesn't even require the full generality of CS, you can do it with something simpler

[humble burrow]

Yeah, probably just vectors, no?

Not doing L^2 CS haha

[dim forge]

there is only one CS, Nyways this isn't relevant to the post so continue elsewhere

[humble burrow]

Yeah.

[uncut parrot]

i know cauchy swartz thank you i couldnt notice

but its chapter 5 and inequalities is in chapter 11

is there any other way to solve

[uncut parrot]

sorry couldnt understand

[dim forge]

think of it as an exercise

[dim forge]

you need the RMS inequality here

[gray crescent]

@uncut parrot

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[grave elbow]

Unable to parse the channel name

[hasty kraken]

Is that the new NCERT?

[dim forge]

its CTPCM

[hasty kraken]

Oh

[uncut parrot]

how to close thread

[humble burrow]

Use +close

[uncut parrot]

+close

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[dim forge]

+close