一、平面极坐标( Plane polar coordinate) 设一质点在Oxy平面内1y 运动,某时刻它位于点A. A(x,y) 矢径r与x轴之间的夹角为 0.于是质点在点A的位置 可由A(r,)来确定 以(r,)为坐标的参考系为 平面极坐标系. 它与直角坐标系之x=rcosθr=x 间的变换关系为:

A matrix is a rectangular array of numbers. A matrix with m rows and n columns is called an m × n matrix. The plural of matrix is matrices. A matrix with the same number of rows as columns is called equal if they have the same number of rows and the same number of columns and the corresponding entries in every position are equal

7.6 DMA控制器8237 7.7 D/A和A/D转换技术

一． 选择题： 1.(B) 2.(B ) 3.(A) 4 .(D) 5.(C) 6.(A) 7.(C) 8.(A) 9.(A) 10.(B) 11.(D) 二． 填空题： 1．自然光或（和）圆偏振光 、线偏振光（完全偏振光） 2．2 、1/4

11.1 概述 11.2 D/A转换器 11.3 A/D转换器

一、 有关D/A、A/D的基本概念 二、 DAC及其接口 三、 ADC及其接口 四、 A/D，D/A应用举例

1. Establish a normal tree. tree branches--Us, C(, R) cot ree(chords)-i,,(, R) 2. Assign voltage and current variables. Assign a voltage (with polarity reference) to every capacitor and a current(with arrow) to every inductor; there are the state variables. Indicate the voltage across every tree branch and the current through every link in terms of the source voltages, source currents,and the state

Any periodic waveform f(t)f(t) can be expressed by a Fourier series provided that (1) If it is discontinuous, there are only a finite number of discontinuous in the period T (2)It has a finite average value over the period T (3)It has a finite number of positive and negative maximums in the period T

例1设a,b为任意实数,证明 I+|a+bl 1+lal 1+b 证我们将从函数f(x)=x的性质着手证明不等式 设f(x) x>0,若0≤x1