"In Grade 2 and early in Grade 3, students learned to use bar models to solve two-step problems involving addition and subtraction. This is extended in this chapter to include multiplication and division.
<span>Both multiplication and division are based on the concept of equal groups, or the part-part-whole concept, where each equal group is one part of the whole. In Grade 2, students showed this with one long bar (the whole) divided up into equal-sized parts, or units. This unitary bar model represents situations such as basket of apples being grouped equally into bags." </span>https://www.sophia.org/tutorials/math-in-focus-chapter-9-bar-modeling-with-multipli
Hello
cos ( x + pi/2) =cos(x)cos(pi/2)-sin(x) sin(pi/2)
= cos(x)×0-sin(x) ×1
cos ( x + pi/2) = - sin(x)
Answer:
C 2/3
Step-by-step explanation:
this is because there are three different types of sandwiches and he picks two out of the three.