Open Middle®
Directions: Using the digits 0 to 9, at most one time each, place a digit in each box to create a cosine function with the given period in degrees.
Hint
What is the relationship between the coefficient of x (usually called b) and the period? How do you calculate the period if you know the value of b?
Given that the period is only two digits, what numbers can you use for b?
Given that the period is only two digits, what numbers can you use for b?
Answer
The coefficient before x is the frequency of the periodic function. To find the period you divide 360 by b. Given that the period is only 2 digits, b>3. The possible answers are therefore:
y = cos 4x and period: 90°
y = cos 5x and period: 72°
y = cos 8x and period: 45°
y = cos 9x and period: 40°
Source: Kate Nerdypoo