Problem Bank

A random taste of what’s inside — refresh for a new set.

You’re seeing 12 random problems out of 3678. Create a free account to browse the full bank with topic filters and endless scroll.

★ 7/10

Symmetric Points on an Ellipse

Two distinct points AA and BB on the ellipse x22+y2=1\dfrac{x^2}2+y^2=1 are symmetric about the line y=mx+12y=mx+\dfrac 12.

1. Find the range of mm. 2. Find the maximum area of $\triangle…

Affine Transformationconic sectionsAM-GManalytic geometry+1
★ 7/10

One Symmetric Pair

Let

f(x)={log⁡ax,x>0,∣x+3∣,−4⩽x<0,f(x) = \begin{cases} \log_a x, & x > 0,\\ |x + 3|, & -4 \leqslant x < 0, \end{cases}

where a>0a > 0 and a≠1a \neq 1. If the graph of f(x)f(x) contains exactly one pair of poi…

functionsReflectionLogarithmsCasework
★ 7/10

An Area Range of a Fixed Chord

Let A,BA,B be two points on the ellipse x28+y22=1\dfrac{x^2}8+\dfrac{y^2}2=1 with chord length ∣AB∣=83|AB|=\dfrac 83. Find the range of the area of △AOB\triangle AOB, where OO is the origin.

ExtremaAffine Transformationconic sections
★ 7/10

Pinning a Sine Wave

Let

f(x)=2asin⁡(ωπx+φ),a,ω>0, ∣φ∣⩽π2,f(x) = \sqrt{2}a\sin(\omega\pi x + \varphi), \qquad a, \omega > 0,\ |\varphi| \leqslant \frac{\pi}{2},

and suppose the line y=ay = a meets the graph of ff at consecutive …

trigonometryExtremaTrigonometric Identities
★ 8/10

An Invariant in a Recursion

Sequences {an}\{a_n\} and {bn}\{b_n\} satisfy a1=1a_1 = 1, b1=2b_1 = 2, and

an+1bn=anbn+2an+4.a_{n+1}b_n = a_nb_n + 2a_n + 4.

1. If additionally bn=2anb_n = 2a_n for all nn, prove that for $n \geqslant …

RecursionsequencesInductionTelescoping+1
★ 5/10

A Derivative Meets a Parameter

Let e\mathrm{e} be the base of the natural logarithm, let f(x)=ex+sin⁡x−2xf(x) = \mathrm{e}^x + \sin x - 2x, and let g(x)g(x) be the derivative of f(x)f(x).

1. Find the equation of the tangent lin…

functionsExtremacalculusMonotonicity
★ 5/10

Permutations That Stay Ahead

Find the number of permutations of 1,2,3,4,5,61, 2, 3, 4, 5, 6 such that for each k=1,2,3,4,5k = 1, 2, 3, 4, 5, at least one of the first kk terms of the permutation is greater than kk.

combinatoricsCountingRecursion
★ 7/10

Height Equals Excess

In triangle ABCABC, the sides opposite angles A,B,CA, B, C are a,b,ca, b, c, the altitude to side BCBC has length hh, and

b+c=a+h.b + c = a + h.

1. If h=23ah = \dfrac{2}{3}a and $k\sin A - \…

plane geometrytrigonometryTrigonometric IdentitiesAM-GM+1
★ 6/10

A Max Scalar Projection

In the plane, e1\boldsymbol e_1 and e2\boldsymbol e_2 are perpendicular unit vectors. A vector a\boldsymbol a satisfies ∣a−4e1∣=2|\boldsymbol a-4\boldsymbol e_1|=2, and a vector $\boldsy…

ExtremaCirclesvectors
★ 7/10

Three Tangled Logarithms

Evaluate

1−2log⁡65⋅log⁡103⋅log⁡152log⁡65⋅log⁡103+log⁡103⋅log⁡152+log⁡152⋅log⁡65.\frac{1 - 2\log_6 5 \cdot \log_{10} 3 \cdot \log_{15} 2}{\log_6 5 \cdot \log_{10} 3 + \log_{10} 3 \cdot \log_{15} 2 + \log_{15} 2 \cdot \log_6 5}.
functionsalgebraLogarithms
★ 8/10

Approaching One From Below

Let a0=12a_0 = \dfrac{1}{2} and

ak=ak−1+1nak−12(k=1,2,…,n).a_k = a_{k-1} + \frac{1}{n}a_{k-1}^2 \qquad (k = 1, 2, \ldots, n).

Prove that

1−1n<an<1.1 - \frac{1}{n} < a_n < 1.
MonotonicitysequencesEstimationTelescoping+1
★ 7/10

Three Zeros of a Palindromic Quartic

Suppose the function

f(x)=x4−6x3+rx2−6x+1f(x)=x^4-6x^3+rx^2-6x+1

has exactly three zeros in (0,3](0,3]. Find the range of the real number rr.

functionsQuadratic EquationsSubstitutionalgebra+1

Sign up to unlock all 3678 problems.