Yesterday, jed's bank account balance was –$26.34. he deposited some money into his account so that the balance is now $42.18. how much did he deposit into his account?

Jed's bank account balance yesterday = -$26.34
Jed's account balance now = $42.18
So Jed's balance has recovered from a negative balance to a positive balance. Now it is required to find the amount of money jed deposited to reach this state.
Let us assume that money deposited by Jed = X
Then
X -26.34 = 42.18
X = 42.18 + 26.34
   = 68.52
So Jed deposited $68.52 in his account.

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.