1 . 已知数列
是等比数列,首项为
,公比为
.
(1)求证:“如果
,
,那么
(
为正整数)”是真命题;
(2)写出(1)中命题的逆命题,判断它的是真命题还是假命题,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(1)求证:“如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eda6dc559d07bc22c9a0ed1e3a6d01d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1a5945ce5c2114af8c18718ca8dc899.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(2)写出(1)中命题的逆命题,判断它的是真命题还是假命题,并说明理由.
您最近一年使用:0次
2 . π为圆周率,a,b,c,d∈Q,已知命题p:若aπ+b=cπ+d,则a=c且b=d.
(1)写出⌝非p并判断真假;
(2)写出p的逆命题、否命题及逆否命题并判断真假.
(1)写出⌝非p并判断真假;
(2)写出p的逆命题、否命题及逆否命题并判断真假.
您最近一年使用:0次
17-18高二·全国·课后作业
3 . 写出下列命题的否定与否命题.
(1)若a2+b2=0,则a=0,b=0;
(2)若一个三角形为锐角三角形,则它的三个内角都是锐角.
(1)若a2+b2=0,则a=0,b=0;
(2)若一个三角形为锐角三角形,则它的三个内角都是锐角.
您最近一年使用:0次
11-12高二上·福建三明·期中
4 . (1)写出命题“若
是偶数,则
是偶数”的否命题;并对否命题的真假给予说明.
(2)求证:“
”是“方程
无实根”的必要不充分条件.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
(2)求证:“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b140e221ddf537b8964fff8557cca0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5707186257494f1fea86066f2778b5.png)
您最近一年使用:0次
11-12高二上·河南驻马店·期中
5 . 写出命题“若
,则
且
”的逆命题、否命题、逆否命题,并判断真假.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f7be7add9015479740638f5cb007cc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eefa44964db83759aff6fc8dd7ef8f28.png)
您最近一年使用:0次