1. 函數(shù)和坐標(biāo)軸所圍成圖形面積是(   ).

A.                                                 B.

C.                                                  D.

2. 二次曲面中,代表橢圓拋物面的方程是(   ).

A.                                   B.

C.                                       D.

3. 過(guò)直線且垂直于平面的平面方程是(   ).

A.                                     B.

C.                                   D.

4. 已知)為某二元函數(shù)的全微分,則常數(shù)需滿足(   ).

A.                                                     B.

C.                                                          D.

5. 設(shè)均為可微函數(shù),且.已知在約束條件

下的一個(gè)極值點(diǎn),下列選項(xiàng)正確的是(   ).

A. 若 ,則

B. 若,則

C. 若 ,則

D. 若,則

1.答案:B.解析:本題考查函數(shù)的定積分的應(yīng)用.

所圍面積都是正數(shù),不存在奇函數(shù)在對(duì)稱區(qū)域積分為零.

.

2.答案:C.解析:本題考查二次曲面標(biāo)準(zhǔn)方程.

A代表橢球面,B代表雙葉雙曲面,D代表二次錐面,故選C.

3.答案:B.解析:本題考查平面的方程.

直線L的方向向量為,平面的法向量,所求平面法向量 .平面過(guò)直線上的點(diǎn),由平面方程的點(diǎn)法式得,即.

4.答案:B.解析:本題考查全微分方程的等價(jià)條件.

設(shè).為某二元函數(shù)的全微分.因?yàn)?img height="42" src="data:image/wmf;base64,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" width="225" />,,所以,即,故選B.

5.答案:D.解析:本題考查多元函數(shù)微分學(xué)的應(yīng)用.

設(shè)

由已知,點(diǎn)在約束條件下的極值點(diǎn),故有

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