Question

Bruce had an EKG to measure his heartbeat rate. After conversion, the function produced could be modeled by a cosine function, and the wave produced a maximum of 4, minimum of −2, and period of pi over 2. Which of the following functions could represent Bruce's EKG read-out?

Answer 1

f(x) = 4 cos pi over 2x − 2
f(x) = 3 cos 4x + 1
f(x) = 3 cos pi over 2x + 1
f(x) = 4 cos 4x − 2

Answer 2

f(x) = A cos (Bx + C) + D
A = amplitude = ½|max - min|
B = (2π)/period
C = phase shift = 0 for this problem
D = vertical shift = max - amplitude

Answer 3

A and D are wrong right?

Answer 4

yes

Answer 5

i think its C

Answer 6

The coefficient of x is 2pi/period, so it should be
\[2 \pi \div \frac{ \pi }{ 2 }\]

Answer 7

oh so its 4

Answer 8

so 4x

Answer 9

yep

Answer 10

i see now its B thank you very much

Answer 11

you're welcome