| 1. | The cosine rather than the sine is customarily used in this case .
在这种情况下，习惯上用余弦函数而不是正弦函数。 |
| 2. | We derive the addition formulas for sine and cosine from the arithmetic of complex numbers .
用复数算术推导了正弦，余弦的加法公式。 |
| 3. | The expression for g can be rewritten in terms of trigonometric sines and cosines .
关于g的表达式可以重写成三角函数的正弦和余弦形式。 |
| 4. | Let's now examine the simplest wave form where the profile is a sine or cosine curve .
现在让我们来考察最简单的波形，它的剖面图是正弦或余弦曲线。 |
| 5. | If a sinusoidal current is sent through a moving coil galvanometer, the meter reads zero .
如果将一正弦电流通入动圈式电流计，那么这电流计的读数为零。 |
| 6. | For simplicity, we assume e to be in the x direction and to vary sinusoidally in the y direction .
为简单起见，我们假定E在X方向上，并在Y方向上正弦式地变化。 |
| 7. | This particular half-sine pulse is only a very approximate model for the actual state of affairs .
这个特定的半正弦脉冲对实际情况来说只是一个非常近似的模型。 |
| 8. | Thus every motion corresponding to any initial curve is no more than a sum of sinusoidal periodic modes .
这样，每一个对应于任一初始曲线的运动不外乎是正弦周期模式的和。 |
| 9. | The case of a harmonic oscillator driven by sinusoidally varying force is an extremely important one in many branches .
在许多领域中受正弦变化力策动的谐振子是一种十分重要的运动。 |
| 10. | Inside the film, the field varies sinusoidally and the entire surface-wave mode propagates alone the horizontal z direction .
在薄膜内，场按正弦函数变化，整个表面波模沿水平Z方向传播。 |
