Qurak

聽起來合理不等於正確

六道語言模型自信卻答錯的題,與引擎算出的結果並列。

靠模式作答的助理,出錯的頻率足以造成影響,而且錯得有規律:答案的形狀是對的。級數的前幾項是對的;積分是一個著名的值,卻配上了錯誤的上下限;因式分解停在肉眼看不出的地方。下面每一列展示模式給出的答案、它出錯的那一項,以及引擎真正計算時傳回的結果。

本頁不點名任何模型。左欄是模式比對在這些題目上普遍會給出的結果,任何一個模型一旦進步,它就過時了;右欄在每次建置時都重新對照引擎驗證,若有偏差,本頁就無法發布。

Series[Tan[x], {x, 0, 9}]

語言模型,靠模式作答

x + x^3/3 + 2x^5/15 + 17x^7/315 + 31x^9/2835 + O(x^11)

出錯的一項: 31x^9/2835

Qurak,實際計算

SeriesData[x, 0, {1, 0, 1/3, 0, 2/15, 0, 17/315, 0, 62/2835}, 1, 10, 1]

建置時已對照引擎驗證

The first four coefficients are common enough to be recalled correctly; the fifth is not. The true coefficient is 62/2835. A series that is right to four terms and wrong at the fifth looks like knowledge and is the shape of a guess.

自己算一遍

Eigenvalues[{{2, 0, 0, 1}, {0, 3, 1, 0}, {0, 1, 3, 0}, {1, 0, 0, 2}}]

語言模型,靠模式作答

{4, 2, 3, 1} - or, from a sign slip in the characteristic polynomial, {4, 3, 2, -1}

出錯的一項: -1

Qurak,實際計算

{4, 3, 2, 1}

建置時已對照引擎驗證

A 4x4 characteristic polynomial has enough terms for one sign to go wrong on the way to the answer, and a wrong sign produces a wrong eigenvalue that still looks like one. Here the matrix decouples into two 2x2 blocks; the engine finds all four exactly rather than approximating the quartic.

自己算一遍

Integrate[Sin[x]/x, {x, 0, Infinity}]

語言模型,靠模式作答

Pi - the integral over the whole real line, quoted for the half line

出錯的一項: Pi

Qurak,實際計算

Pi/2

建置時已對照引擎驗證

The Dirichlet integral is famous enough to be recalled, and famous enough to be recalled with the wrong limits: the value over (-inf, inf) is Pi, over (0, inf) it is Pi/2. Both facts are true; attaching the right one to the limits written down is the computation.

自己算一遍

FactorInteger[987654321987]

語言模型,靠模式作答

{{3, 1}, {329218123329, 1}} - the cofactor declared prime by inspection

出錯的一項: 329218123329 declared prime

Qurak,實際計算

{{3, 1}, {329281, 1}, {999809, 1}}

建置時已對照引擎驗證

Dividing out the 3 is easy; deciding whether the twelve-digit cofactor is prime is not something inspection can do, so a plausible answer stops there and calls it prime. The engine factors it, and it is not.

自己算一遍

PowerMod[3, 1000000, 1000000007]

語言模型,靠模式作答

1 - by Fermat's little theorem, misapplied: 3^(p-1) is 1 mod p, but the exponent here is not p-1

出錯的一項: 1

Qurak,實際計算

64935414

建置時已對照引擎驗證

The theorem is real and the shape of the problem invites it, but 10^6 is not 10^9+6. The correct residue is reached only by actually reducing, which is a few hundred squarings - trivial for an engine and impossible by inspection.

自己算一遍

Sum[1/n^4, {n, 1, Infinity}]

語言模型,靠模式作答

Pi^4/96, or Pi^4/45 - a neighbour of the right constant

出錯的一項: Pi^4/96

Qurak,實際計算

Pi^4/90

建置時已對照引擎驗證

zeta(2) = Pi^2/6 is remembered by everyone; zeta(4) is remembered as 'Pi^4 over something', and the something is where a recalled answer diverges from a computed one. 90 is right; 96 and 45 both appear in nearby identities and are both wrong here.

自己算一遍

您的助理可以把數學交給引擎

Qurak 是一個 MCP 伺服器。連接之後,Claude、Cursor、VS Code 或任何 MCP 用戶端都會去計算而不是猜測——而且在免費方案上就開放。或者就在這裡試算一個運算式,不需帳戶。

匿名每小時 5 次計算,1 秒計算時間,僅限數學運算。註冊帳戶即可解除這三項限制。