Final answer:
The primary purpose of using persuasive techniques in promoting a gadget is to convince the audience of its advantages and encourage them to make a purchase.
Step-by-step explanation:
The primary purpose of using persuasive techniques in a sales representative's paragraph for promoting a gadget is to convince the public about the advantages of buying the gadget. This is achieved by engaging the audience, establishing credibility, and convincing them with evidence that supports the advantages and benefits of the product. In effective persuasive writing, such as a sales pitch, the writer's intention is to not only inform but actively persuade the reader to adopt a new belief or behavior, which in this case is purchasing the gadget. The introduction of the persuasive text should grab the reader's attention, present the topic clearly, and provide a clear statement of the argument.