Vault Of Euclid

Wednesday, 5 August 2026

10 problems across Real & complex analysis, Calculus and Linear algebra.

21
Days
210
Problems served
1 warmup Series of numbers Real & complex analysis
Find the first three nonzero terms of the Maclaurin series for \(\tan x\).
maclaurin-seriestaylor-seriesderivativestrigonometric-functionschain-ruleproduct-ruleevaluate-seriestangent-functionhigher-order-derivativescalculus-iipower-seriesfind-series-expansion

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2 core Antiderivatives Calculus
Evaluate \( \int (4-2t^2)^7 t \, dt \).
integrationsubstitutionindefinite-integralpolynomialpower-rulecalculus-ievaluate-integralu-substitutionantiderivativechain-rule-reverse

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3 core Differential equations Calculus
Rewrite the system \[ x'' = f(t, x, x', y, y', y'') \] \[ y''' = g(t, x, x', y, y', y'') \] as a first order system.
differential-equationssystems-of-differential-equationsfirst-order-systemhigher-order-differential-equationsreduction-of-orderstate-variableschange-of-variablesordinary-differential-equations

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4 hard Limits Calculus
\(\lim_{x\to 0} \frac{\cos 2x - \cos x}{\sin^2 x}\)
calculus-ilimitsevaluate-limitl-hopitalindeterminate-formstrigonometric-functionssinecosinechain-ruledouble-angle-identityderivatives

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5 core Multivariable calculus Calculus
Let \(\vec{r}(t) = \langle \cos t, \sin t, t \rangle\). Compute \(\vec{r}'(t)\) and \(\vec{r}'(\pi/2)\). Sketch \(\vec{r}'(\pi/2)\) with its initial point at the origin and at \(\vec{r}(\pi/2)\).
vector-valued-functionsderivativesevaluationsketchingtangent-vectormultivariable-calculuscalculus-iiiparametric-equationsspace-curvehelixtrigonometric-functionsfind-derivative

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6 core Parametric equations and vector functions Calculus
Find all points on the curve \( x = \sec \theta, y = \tan \theta \) at which horizontal and vertical tangents exist.
parametric-equationsderivativeshorizontal-tangentvertical-tangenttrigonometric-functionssecanttangentcalculus-iicurve-sketchingfind-pointsevaluate-derivative

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7 core Polar coordinates Calculus
\( a_{n}=\frac{n^{2}+5}{\sqrt{4n^{4}+n}} \)
limit-of-a-sequenceindeterminate-formrational-functionsquare-rootasymptotic-behaviordivide-by-highest-powercalculus-iireal-analysisevaluate-limitsequencesalgebraic-manipulationinfinity

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8 warmup Techniques of integration Calculus
Let \( \mathcal{R} \) be the region bounded by the curve \( y = \frac{\ln x}{x} \), the \( x \)-axis, and the line \( x = e \). Find the area of \( \mathcal{R} \).
calculus-idefinite-integralarea-under-curvenatural-logarithmintegration-by-substitutionfundamental-theorem-of-calculusevaluate-integralfind-arearoots-of-functionslogarithmic-functionsrational-functionsu-substitution

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9 core Eigenvalues and eigenvectors Linear algebra
Subtract \(\lambda = 7\) down the diagonal of A to obtain

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10 core Vector spaces Linear algebra
Suppose \( z = 5 + 3i \) and \( w = 2 - 4i \). Find: (a) \( z+w \), (b) \( z- w \), (c) \( zw \). Use the ordinary rules of algebra together with \( i^2 = -1 \) to obtain a result in the standard form \( a + bi \).
complex-numberscomplex-arithmeticadditionsubtractionmultiplicationreal-partimaginary-partimaginary-unitalgebraic-expansionstandard-form

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