(1)求值: lg 5 2 + 2 3 lg8+lg5•lg20+(lg2 ) 2
1个回答

(1) lg 5 2 +

2

3 lg8+lg5•lg20+(lg2 ) 2

= 2lg5+

2

3 lg 2 3 +lg5(1+lg2)+(lg2 ) 2

=2lg5+2lg2+lg5(1+lg2)+(lg2) 2
=2(lg5+lg2)+lg5+lg5•lg2+(lg2) 2

=2+lg5+lg2(lg5+lg2)=3.

(2) (0.0081 ) -

1

4 -[3×(

7

8 ) 0 ] -1 × [8 1 -0.25 +(3

3

8 ) -

1

3 ] -

1

2 -10×0.02 7

1

3

= ((0.3 ) 4 ) -

1

4 - 3 -1 ×[( 3 4 ) -

1

4 +(

3

2 ) -1 ] -

1

2 -10× ((0.3 ) 3 )

1

3

=

10

3 -

1

3 (

1

3 +

2

3 ) -

1

2 -10•0.3

=

10

3 -

1

3 -3

=0.