Final answer:
Regulatory signs with a red circle and diagonal line mean no action is permitted, the Necessary and Proper Clause has expanded federal power, and vectors can indeed form right-angle triangles with their components.
Step-by-step explanation:
The statement regarding a regulatory sign with a red circle and a diagonal line through it is true. Such a sign does indeed indicate that some action is prohibited, whether it's entering a street, making a particular maneuver, or engaging in a certain activity in that zone.
In Exercise 9.3.1, the statement that the necessary and proper clause has had the effect of limiting the power of the national government is false. The Necessary and Proper Clause, also known as the Elastic Clause, has done quite the opposite by expanding federal power to include actions that are not specifically enumerated in the Constitution but are deemed necessary to execute the government's constitutional responsibilities.
Regarding the true or false question about vectors forming the shape of a right angle triangle with their x and y components, the answer is true. A vector can be broken down into two perpendicular components, x (horizontal) and y (vertical), which together can form a right triangle with the vector itself being the hypotenuse.