Tripling fundamental frequency

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To achieve a fundamental frequency three times greater than the original 1045 Hz of a bass violin string, the string's vibrating length must be adjusted. The initial calculations suggest that placing fingers 0.3 m from the lower fixed end is correct, based on the relationship between frequency and string length. However, a teacher proposes using the speed of sound in air, leading to a different answer of approximately 0.84 or 0.084 m. The discussion emphasizes that the question pertains to the string's physical properties rather than sound perception through air. Ultimately, the consensus leans towards focusing solely on the string's length for accurate frequency adjustment.
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So the question goes like this- The fundamental frequency of a bass violin string is 1045 Hz and occurs when the string is 0.900 m long. How far from the lower fixed end of the bass violin should you place your fingers to allow the string to vibrate at a fundamental frequency 3 times as great?

I say you take (2*.9)*1045 to get 1881 m/s because of v=f*w, then you take (1881/(1045*3))/2 to get .3 because of f=v/2l, and .3 would be the answer which would make sense since .3=(1/3).9

My teacher who is a smart man says you would disregard the information you got about the length of the string (the 0.900 m) and just take (340(speed of sound in air)/(3*1045))/2 or something like that he got like .84 or .084 which doesn't add up to the equation I just said, but that's what he said to do because he said it has to travel through air so we can hear it.

I think that that is irrelevant because it is not asking for how we perceive the frequency but rather what the string is actually doing. So I just kinda want an answer to know whose right so if this is on my text I know what to do. Thank you
 
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I agree with you. Nothing to do with air.
 
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