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Description

De Souza proposes to himself the problem of determining the function ϕ which ( f, F being given functions, and the limits α, β of the integration being also given) satisfies the equation ∫βαf(x, θ) ϕ (x + θ) dθ = Fx. He observes, that, unlike the methods employed in his former memoir, and the solutions there employed, which are quite rigorous, the methods of the present memoir depend upon developments into series, the strictness of which has been contested by some mathematicians ; but that passing over these difficulties, he has solved the famous problem, the solution of which has been vainly sought after for the last two hundred years, because on the above-mentioned equation depends the integration of the generally linear equation of any order whatever of two variables, and consequently the whole integral calculus.

Subject: Mathematics / Calculus

Received 25 April 1836. Communicated by Dr [William] Sharpey.

Written by de Souza at 29 Brompton Square, London.

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 8 of the Proceedings of the Royal Society as 'On the determination of unknown functions that are involved under definite integrals'.

Reference number
AP/38/26
Earliest possible date
25 April 1856
Physical description
Ink on paper
Page extent
125 pages
Format
Manuscript

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Citation

Unpublished paper, 'Second memoir upon the determination of unknown functions that are involved under definite integrals' by Joaquim Gomes de Souza, 25 April 1856, AP/38/26, The Royal Society Archives, London, https://makingscience.royalsociety.org/items/ap_38_26/unpublished-paper-second-memoir-upon-the-determination-of-unknown-functions-that-are-involved-under-definite-integrals-by-joaquim-gomes-de-souza, accessed on 18 January 2026

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    The 'Archived Papers' collection is comprised of original manuscript scientific papers and letters submitted to the Royal Society which remained unpublished or were abstracted in the journal 'Proceedings of the Royal Society' published from 1830 onwards.

    Dates: 1768 - 1989

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