Consider the relational schema below: Students(sid: integer, sname: string, major: string) Courses(cid: integer, cname: string, hours: integer) Enrollment(sid: integer, cid: integer, grade: real) Write a relational algebra expression that satisfies this query? Find the distinct names of all students that take at least three courses and major in "Philosophy".

Robots with telescoping arms are sometimes used to perform tasks (e.g., welding or placing screws) where access may be difficult for other robotic types. during a test run, a robot arm is programmed to extend according to the relationship r = 3 + 0.5cos(4θ) and the arm rotates according to the relationship θ=−π4t2+πt , where r is in feet, θ is in radians, and t is in seconds. use a computer program to plot the path of tip a in x and y coordinates for 0 ≤ t ≤ 4s.

The forerunner to cell phones, pdas, and smartphones was

Ulia is planning to attend the same private four-year college her parents attended. she wants to save at least $18,000 in four years to contribute to her college education. which monthly deposit amounts can julia use to achieve her goal? check all that apply.