Question

Which of the following would best represent a cosine function with an amplitude of 3, a period of pi over 2, and a midline at y = −4?

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

Answer 1

@LegendarySadist

Answer 2

The amplitude is the number before the trig function (sine, cosine, etc.). So we want a 3 before the cos in this case.

Answer 3

ok

Answer 4

can u help

Answer 5

It will usually be written out like this \[\large acos(bx-c)+d\\\large amplitude~=~a\\\\\large period~=~\frac{2pi}{b}\]

Answer 6

The midline is the point halfway between the top and bottom of the wave. The midline of a cos function is usually 0. So to change it to 4 smaller, we have to make the vertical change (the d in my example) equal -4. So set d=-4

Answer 7

A

Answer 8

Wrong. Did you just guess?

Answer 9

No

Answer 10

Nevermind i figured it out thanks anyways

Answer 11

\[\large amplitude=a\\\large amplitude=3\\\large a=3\] So in \(\large acos(bx)+d\), \(\large a=3\)

Answer 12

So did you get the answer then?