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Can you integrate this?
Created 25th May 2014 @ 15:10
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It’s not since you should set your calc to radians. In that case pi = 180degrees so sin pi/2 = sin 180/2 = sin 90 = 1
Quoted from jx53
Yeah. But what if it is sin (3.14/2)
Have you met radians before?
If you’re given a question that requires you to integrate trig functions, they have to be in radians (citation needed). So find the radians setting on your calculator, and then try.
Quoted from jx53
Yeah. But what if it is sin (3.14/2)
that will work if your calculator is in radians, but most calculators are in degrees by default.
3.14 is an estimate of pi, so it won’t give you the exact result.
FriendlyCow — no, they don’t :D sin3x can be integrated to -(1/3)cos3x +c and the x can still be either in radians or degrees, whichever suits you better
And as a triple post cause i’m dumb (feel free to merge them anyone, sorry): you can convert your pi into degrees by multiplying by 180 and dividing by pi, hence giving you the 90 degrees Permzilla mentioned
Last edited by Solid,
Quoted from Rex
[…]
Have you met radians before?
I have, but lets make an imaginary situation where the value is 3,14/2. No radians. Could that be integrated? If so what would the answer be?
How do i know for sure if the question means radians?
Quoted from jx53
[…]
I have, but lets make an imaginary situation where the value is 3,14/2. No radians. Could that be integrated? If so what would the answer be?How do i know for sure if the question means radians?
You don’t but it’s a pretty reasonable assumption they expect you to work in radians since sin(pi/2) = 1.
They would accept an answer in degrees it just wouldn’t be as “neat”.
From here on up you pretty much want to ditch degrees in favour of radians anyway. Get used to them!
Last edited by Rex,
Quoted from Rex
[…]
You don’t but it’s a pretty reasonable assumption they expect you to work in radians since sin(pi/2) = 1.
They would accept an answer in degrees it just wouldn’t be as “neat”.
From here on up you pretty much want to ditch degrees in favour of radians anyway. Get used to them!
Alrighty. Huge thanks to everyone who bothered to answer!
Should start charging refined for this. ;)
Let’s entertain that thought: If the question was asking for any other constant, such as sin(3.14/2) in degrees * cos(x), you’d just treat it as a constant and use the product rule for integrating : uv – integration(v*(du/dx)). The answer would therefore be
Sin(1.57)*Sin(x) +sin(x)*0 = sinx * sin(1.57)
So, treating it as degrees, to 3s.f., your integration would be 0.0274sin(x) +c
Last edited by Steve!,
Quoted from Steve!
Let’s entertain that thought: If the question was asking for any other constant, such as sin(3.14/2) in degrees * cos(x), you’d just treat it as a constant and use the product rule for integrating : uv – integration(v*(du/dx)). The answer would therefore be
Sin(1.57)*Sin(x) +sin(x)*0 = sinx * sin(1.57)
So, treating it as degrees, to 3s.f., your integration would be 0.0274sin(x) +c
It’s called integration by parts.
And you don’t need it since you really should know that integral(acos(x)) = asin(x) + c because you’re dealing with a constant, not another function of x.
Got more work for you, Timon!
If you proof that the real part of every non-trivial zero of the Riemann zeta function is 1/2, I’ll give you 1 000 000$ / 0.24$/ref = 4 166 666 ref and 2 reclaimed for your effort.
Edit: fuck, that’s about double the amount of ref that exists in the tf2 economy now
Last edited by BenBazinga,
Quoted from BenBazinga
Got more work for you, Timon!
If you proof that the real part of every non-trivial zero of the Riemann zeta function is 1/2, I’ll give you 1 000 000$ / 0.24$/ref = 4 166 666 ref and 2 reclaimed for your effort.
The whole million? Surely just take my proof and give me $50k. ;)
Quoted from Rex
[…]
The whole million? Surely just take my proof and give me $50k. ;)
How sweet!
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