积的乘方专项练习50 题(有答案)
知识点:
1.积的乘方法则用字母表示就是:当n 为正整数时,( ab)n=_______.2.在括号内填写计算所用法则的名称.
(- x3yz2)2
= (- 1)2( x3)2y2( z2)2()
=x 6y2z4()
3.计算:
(1)(ab2)3=________;(2)(3cd)2=________;
( 3)(- 2b2)3=________ ;(4)(-2b)4=________;
(5)-( 3a2b)2 =_______;( 6)(-3
a2b)3=_______;2
(7) [ ( a- b)2] 3 =______;( 8) [ - 2( a+b) ] 2 =________.
专项练习:
( 1)(-5ab)2(2)-(3x2y)2
( 3)(11
ab
2
c
3
)
3
(4)
2 3
( 5)2(6)11× 411
( 7) (-a 2) 2· (-2a 3) 2(8)(-a3b6)2-(-a2b4)3
(9)-(-x m y)3·(xy n+1)2
2 2
(10) 2(a b )2+(a b )
(11) (-2 x2y ) 3+8(x 2) 2· (-x 2) · (-y 3)
(12)(- 2× 103)3
(13)( x2)n·x m-n
(14) a2·(- a)2·(- 2a2)3
(15)(- 2a4)3+a6· a6
(16)(2xy2) 2-(-3xy2) 2nnn
(17)0.256( 32)2
(18)(x4)2(x2 ) 4x( x2 )2x3( x)3 ( x2 )2 ( x) ;
(19)(- 1
a 3 n
b m-1)2(4a 3 n b)2
4
(20)( -2a 2 b)3 +8(a 2)2·( -a )2·( -b )3(21)22 m 116 8m 1( 4m ) 8m(m 为正整数 )(22)(-3a 2)3· a 3 +(-4a )2·a 7 - (5a 3)3( 23)3a2b 2( ab) 2
( 24)(a3 )2( a 2 )3
( 25) [ (- 2
) 8
×( 3
) 8 ] 7
3 2
( 26) 8 1999 ·() 2000
(27) ( 2 a b) ( ab )
2
3
1
2 2
2
(28) ( 3 a 3 ) 2 a 3
( 5a 3 ) 3
(29) [ ( 2x 2 )3 ]2
(30)
(1
)9 ( 8)9 8
(31) (5
)2009(2 3)2010 135
(32)(2102 )2(3103 ) 3.
(33)a4( 3a3)2( 4a 5 ) 2
(34)( a4b2)3( a2b3)2
( 35) (21) 20·(3) 21.(11111) 10 ? (10 9 8 2 1)10.
3710982
(37)已知2a3, 3a 4 ,求 6 a.
(38) (a3a x ) y a20,当 x 2 时,求y的值.
(39 )化简求值:( -3a 2 b)3 -8 ( a 2)2·( -b )2·( -a 2 b),其中 a=1, b=-1.
( 40)先完成以下填空:
( 1) 26× 56=()6=10( )(2)410× 2510=()10=10( )
你能借鉴以上方法计算下列各题吗
(3)(- 8)10×
(4)× 42006
(5)(- 9)5·(-2
)5·(
1
)5
3 3
(41)已知 x n=2, y n=3,求( x2y)2n的值.
( 42)一个立方体棱长为2× 103厘米,求它的表面积(结果用科学记数法表示).
(43) 已知2m=3,2n=22,则22m+n的值是多少
3
18
3
4 ,求
(44) 已知9a2的值
3a
(45 ).已知 10 5,106
23
的值,求 10
( 46)已知:x n 5 , y n3,求 ( xy) 2n的值.
n n
求 (x 2
n -x 2 n的值。
( 47) 已知 x =5,y=3,y)
(48) 若有理数 a,b,c 满足 (a-1) 2+|c+1|+|b
|=0,试求a3n+1b3n+2- c4n+2 2
(49)比较大小: 218× 310与 210×3 18
(50)观察下列等式:
32
1 =1 ;
1 3+23=32;
1 3+23+33=62;
1 3+23+33+43=102;
(1)请你写出第 5 个式子: ______________(2)请你写出第 10 个式子: _____________(3)你能用字母表示所发现的规律吗试一试!
答案 :
知识点:
1. a n b n 2 .积的乘方法则,幂的乘方法则
3.( 1) a 3b 6 (2) 9c 2d 2 ( 3)- 8b 6 ( 4) 16b 4 ?
( 5)- 9a 4b
2
( 6)-
27
a 6
b 3 ( 7)( a - b ) 6 ( 8) 4(a+b ) 2
8
专项练习:
(1)
25a 2 b 2
( 2) -9x 4 y
4 ( 3) -
64
a 3
b 6 c
9
( 4)
1
8
6
27
25
x
y
(5) 2m 6m
( 6) -1
(7)4a 10
( 8)2a 6 b 12 (9) x
3m 2 y
2 n 5
( 10) 3a 2 n b 2 n ( 11) 7x 6 y 3 ( 12) - 8×109 ( 13) x m+n ( 14) -8a 10 ( 15)- 7a 12
( 16)- 5x 2y 4
(17)
1
( 18)0
4
(19) a 12 4 n b 2m
( 20)-16a 16 b 3 (21) 0
( 22)-136a 9
( 23) -2a 2 b 2 ( 24) 0 ( 25) 1
( 26)
(27) -2a 8 b 7
(28) 4a 9
(29) 64x
12
(30) 1
(31) 13
(32) × 10 13
5
(33) -7a 10
( 34) a 16b 12 (35) 3
(36)1
7
(37) 6 a =(2 ×3) a =2 a ×3 a =3×4=12
( 38)
3y+xy=20
当 x=2 时, 3y+2y=20
Y=4
(39 )
原式 =-19a 6 b 3 =19
( 40)
( 1) 2× 5, 6 ( 2) 4× 25, 20 ( 3) 1 (4) ( 5) 32
( 41) ( x 2y ) 2n =x 4n y 2n =( x n ) 4 ( y n ) 2 =2 4 × 3 2
=144
2
( 42) 6×( 2× 103 ) =× 107 厘米 2
2m+n
m
n
( 43) 2
= ( 2 ) 2 2
=36
(44) 左边 =( 3 2
a 2
) 3
( 1
) 8
=3 6 a 6
( 1
) 8
= 1
a 6
3
3 9
1
a 6 =4
9
a
6
=36
( a 3 ) 2
=36
a
3
=6或 -6
(45 ) 102 3 =( 10 a ) 2 ( 10 b ) 3 =5 2 × 6 3
=5400
( 46)提示: (xy)
2n
n 2nn 2
×4) 2
=[(xy) ] =(x ·y ) = (5 =400.
2
n -x2n =x 2 n y n -x 2 n =5 2× 3-5 2 =50( 47) (x y)
(48) 由意知: a=1 b=0 c=-1
a 3n+1b3n+2- c4n+2
3n+13n+24n+2
=1× 0- ( -1 )
=-1
(49) 因:218× 310=(2×3)10×28
10×318
( 2×3)10× 3 8
2=
所以:
218×310<210×318 (50)( 1) 13+23+33+43+53=152
(2) 13+23 +? ? +103=552
( 3) 13+23 +?? +n3=[ n(n1)
]2
2