(b) Find the Laplace transform of f(t) = t + (1−4t)u(t−3), where u(t) is unit step function. (5%)

1. Translate the paragraphs into Chinese.A. Many freshwater resources are contaminated through human activities. The major types of water pollution include excessive nutrition produced from agriculture, toxic chemicals such as pesticides and metals, and thermal pollution produced from thermal power plant. (25%)