matlab中如何定义绘图坐标的X轴是以2为底的呢?

>> x=2.^(-10:10)

x =

1.0e+003 *

Columns 1 through 10

0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 0.0001 0.0003 0.0005

Columns 11 through 20

0.0010 0.0020 0.0040 0.0080 0.0160 0.0320 0.0640 0.1280 0.2560 0.5120

Column 21

1.0240

>> y=sqrt(1:21)

y =

Columns 1 through 10

1.0000 1.4142 1.7321 2.0000 2.2361 2.4495 2.6458 2.8284 3.0000 3.1623

Columns 11 through 20

3.3166 3.4641 3.6056 3.7417 3.8730 4.0000 4.1231 4.2426 4.3589 4.4721

Column 21

4.5826

>> plot(log2(x),y)