so set 2sin (30t) + 5 = 3
2sin (30t) = -2
sin (30t) = -1
We know sin (3π/2) = -1
so 30t = 3π/2
t = π/20 = .157 seconds
since the period of the function is 2π/30 = appr .209 seconds
this boat is bouncing up and down about 5 times a second !!
This question is flawed in a major way.
you define t as seconds, yet in the equation you include the ° sign to show degrees. You can't mix units like that.
If you solve it with 30t in degrees, then the wording makes no sense
I hope they did not do this:
sin(30t) = -1
30t = 270 degrees
t = 9 degrees !!!!!!
Looks like they did!!! WOW
I can't figure out this one question...
A ship is docked in port and rises and falls with the waves. The function d(t) = 2sin(30t)°+5 models the depth of the propeller, d(t), in metres at t seconds.
e) within the first 10 seconds, at what times is the propeller at a depth of 3m?
How do you do this problem?? The answer is 9 seconds.
4 answers
I haven't learned any of this with π incorporated into it. I think my teacher mentioned that we do it in grade 12? Radians and such... I'm in grade 11 though.
This question is straight out of the textbook so I guess they did do that.. And they actually mix units like that a lot! Many of the questions in this section of the textbook have equations that look like the one I posted
This question is straight out of the textbook so I guess they did do that.. And they actually mix units like that a lot! Many of the questions in this section of the textbook have equations that look like the one I posted
Is there another way to solve this problem? Without using π
π radians is 180°
3 answers