设A为n维单位球面Sⁿ的可数子集,证明Sⁿ~ A是Sⁿ的连通子集（n≥2).

A.A=2E B.A=-E C.A-E可逆 D.A不可逆

设f=x^TA x是一个实二次型， 若有实n维向量<img src='https://img2.soutiyun.com/ask/2020-12-29/978125347407201.png' />证明：必有实n维向量<img src='https://img2.soutiyun.com/ask/2020-12-29/97812535927688.png' />

设<img src='https://img2.soutiyun.com/ask/2020-08-12/966096879233995.png' />,且n≥2为正整数，求Aⁿ-2A^n-1

A.(30.88，32.63) B.(31.45，31.84) C.(31.62，31.97) D.(30.45，31.74)

设随机变量<img src='https://img2.soutiyun.com/ask/2020-07-27/964689141865362.png' />.则()。 A.U~X²(n} B.U~x²(n-I) C.U~F(n.1) D.U~F(1.n)

设<img src='https://img2.soutiyun.com/ask/2020-08-14/966244002022246.png' />则Aⁿ=(). <img src='https://img2.soutiyun.com/ask/2020-08-14/966244012904869.png' />

设A是n阶(n≥2)可逆矩阵,Aⁿ是A的伴随矩阵，证明: <img src='https://img2.soutiyun.com/ask/2020-08-12/966097950834287.png' />

设A为n阶方阵，|A|≠0，A^-1为A的伴随矩阵，若A有特征值<img src='https://img2.soutiyun.com/ask/2020-12-29/978122571227413.png' />，求(A')2+E的一个特征值。

设a∈Rⁿ,a=(a₁,a₂,...,a_n)^T≠0 求证: <img src='https://img2.soutiyun.com/ask/2020-08-16/966461113345045.png' /> 是正交矩阵。

设X₁，X₂，...X_n(n≥2)为来自正态总体N(0，1)的简单随机样本，<img src='https://img2.soutiyun.com/ask/2020-07-31/965062468168756.png' />为样本均值，S²为样本方差，则正确的是()。 <img src='https://img2.soutiyun.com/ask/2020-07-31/965062477119268.png' />

设矩阵<img src='https://img2.soutiyun.com/ask/2020-08-14/966266104023409.png' />.则A²=()，Aⁿ=()。

设<img src='https://img2.soutiyun.com/ask/2021-02-26/983181956326611.jpg' />，求Aⁿ。

设F是n维欧几里得空间Rⁿ中有界闭集,A是F到自身中的映射,并且适合下列条件:对任何x.γ∈F(x≠γ).有<img src='https://img2.soutiyun.com/ask/2020-08-13/966176163179713.png' /><img src='https://img2.soutiyun.com/shangxueba/ask/50574001-50577000/50576074/spacer.gif' />证明映射A在F中存在唯一的不动点.

设<img src='https://img2.soutiyun.com/ask/2020-08-12/966093934497566.png' />矩阵A满足AP=PM,求Aⁿ.

设A、B为n阶可逆矩阵，且A<img src='https://img2.soutiyun.com/ask/2020-12-03/97586079384016.jpg' />B，试证：A^-1<img src='https://img2.soutiyun.com/ask/2020-12-03/97586079384016.jpg' />B^-1。