Then
You can also use the half-angle identity,
. Since
So you are in the first quadrant; work with or
Here,
Using the calculator, . Again, .
26 . D
Always remember that percents can be expressed as fractions. The fraction of all the items
that were considered acceptable was
Therefore, the fraction of the items produced on the first day that were acceptable must
also have been To find the number of items that were acceptable, simply multiply the
total amount produced on the first day by the fraction: (10,830) = 7,581. Thus, 7,581 items
were produced on the first day that were considered acceptable.
27 . D
The function f maps every point (x,y) to the point (x, −8x + 3y). The goal is to find a point such
that f(x,y) = (x,y) or (x, −8x + 3y) = (x,y).
In the Cartesian coordinate system, two points are the same if their x and y values are the
same. Therefore, the solution of this equation can be simplified into two separate
equations: x = x and y = −8x + 3y.