We have 112.5 = 225/2; cos112.5 < 0 because 90 < 112.5 < 180;
cos 112.5 = cos(225/2);
We use the trigonometric formula: cos(x/2) = -

;
Then, cos(225/2) = -

;
We have the formula: cos(270 - x) = -sinx (because cos(a-b) = cosacosb + sinasinb);
Then, cos225 = cos(270-45) = -sin45 = -

Finally, cos112.5 = -
The correct answer to this is C
Answer:
389
Step-by-step explanation:
MARK BRAINLIEST PLEASE
Using the equation y=9x you can substitute x for the hours. Y=9 times 5 and y=9 times 8. Y=45 and y=72. The range is $45-$72
Steps
find the Least Common Multiple of the denominators (which is called the Least Common Denominator).
Change each fraction (using equivalent fractions) to make their denominators the same as the least common denominator.
Then add (or subtract) the fractions, as we wish!
your denominators stay the same so its 20