设A为m×n矩阵，B为n×，n矩阵，若AB=E，则( ) A: r(A)=m，r(B)=m B: r(A)=m，r(B)=n C: r(A)=n,r(B)=m D: r(A)=n，r(B)=n

若设变压器初、次级线圈的匝比为N=N A: R=NR B: R=NR C: R=R/N D: R=R/N

S为细胞质不育基因，N为细胞质可育基因，r为细胞核不育基因，R为细胞核可育基因。下列杂交何者可产生雄性不育系（ ）。 A: S(r r) × N(RR) B: S(r r) × N(r r) C: N(R r) × S(r r) D: N(r r) × N(r r)

n×n齐次线性方程组存在非零解的充要条件是： A: r(A)=n B: r(A)>n C: r(A)≤n D: r(A)

命题“∀x∈R，∃n∈N*，使得n≥x2”的否定形式是（） A: ∀x∈R，∃n∈N*，使得n2 B: ∀x∈R，∀n∈N*，使得n2 C: ∃x∈R，∃n∈N*，使得n2 D: ∃x∈R，∀n∈N*，使得n2

设\({A_{m \times n}},{B_{n \times k}}\),若\(AB = O\),则下列选项正确的是（ ） A: \(R(A) + R(B) = n\) B: \(R(A) + R(B) \le n\) C: \(R(A) + R(B) \ge n\) D: \(R(A) + R(B) > n\)

n元齐次线性方程组有非零解，则（ ）。 A: R(A)<n B: R(A)=n C: R(A)>n D: R(A)=0

求给定自然数m和n的最大公约数。请完善程序。 Private Sub Command1_Click() Dim m As Integer, n As Integer, r As Integer m = Text1.Text n = Text2.Text If m < n Then r = m: m = n: n = r Do r = m Mod n m = n n = r Loop Until__________ Text3.Text = m End Sub Private Sub Command2_Click() Dim m As Integer, n As Integer, r As Integer m = Text1.Text n = Text2.Text If m < n Then r = m: m = n: n = r r = m Mod n Do Until _______ m = n n = r r = m Mod n Loop Text3.Text =____ End Sub Private Sub Command3_Click() Dim m As Integer, n As Integer, r As Integer m = Text1.Text n = Text2.Text If m < n Then r = m: m = n: n = r Do r = m Mod n m = n n = r Loop While________ Text3.Text =______ End Sub Private Sub Command4_Click() Dim m As Integer, n As Integer, r As Integer m = Text1.Text n = Text2.Text If m < n Then r = m: m = n: n = r r = m Mod n Do While______ m = n n = r r = m Mod n Loop Text3.Text =____ End Sube73f1fd63959cc8362d8c82d419c2353.png

设A为n阶方阵，且满足A2=A，则(  )．(A)r(A)=n  (B)r(A)=0(C)r(A)+r(E-A)=n  (D)r(A)=r(E-A)

n元非齐次线性方程组,当()时,方程组无解。 A: R(A) B: R(A)=n C: R(A)<R(B) D: R(A)=R(B)<n