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Homework Statement
1) When a camera flash goes off, the batteries immediately begin to recharge the flash's capacitor, which stores electric charge given by the following. (The maximum charge capacity is M and t is measured in seconds.)
Q(t) = M(1 - e-t/a)
(a) Find the inverse of this function and explain its meaning.
2. Let f(x) = 2 + x2 + tan(πx/2), where -1 < x < 1.
(a) Find f(f -1(4)).
Homework Equations
n/a
The Attempt at a Solution
(1) Q = M(1 - e^-t/a)
Q/M = 1 - e^-t/a
e^-t/a = 1 - Q/M
-t/a (ln e) = ln(1 - Q/M)
-t/a = ln(1 - Q/M)
t = -a[ln(1 - Q/M)]
That's not right.
(#2.) x = 2 + y^2 + tan(π*y/2)
4 = 2 + y^2 + tan(π*y/2)
*plug into wolfram alpha... y~0.642
f(x) = 2 + x2 + tan(πx/2) original formula
f(.642)= 2 + (.642^2) + tan (.642π/2)
f(.642)=2.4293
That's not right either.
I'm not really seeing where I went wrong in either of them..any help is appreciated.