Answer:
The values of and
for a linear system with infinitely many solutions are -2 and 5, respectively.
Step-by-step explanation:
Let , if this linear system has infinitely many solutions, then the following conditions must be met:
and
.
and
The values of and
for a linear system with infinitely many solutions are -2 and 5, respectively.
x/tan(x) is an even function
sec(x)/x is an odd function
<h3>Explanation:</h3><em>x/tan(x)</em>
For f(x) = x/tan(x), consider f(-x).
... f(-x) = -x/tan(-x)
Now, we know that tan(x) is an odd function, so tan(-x) = -tan(x). Using this, we have ...
... f(-x) = -x/(-tan(x)) = x/tan(x) = f(x)
The relation f(-x) = f(x) is characteristic of an even function, one that is symmetrical about the y-axis.
_____
<em>sec(x)/x</em>
For g(x) = sec(x)/x, consider g(-x).
... g(-x) = sec(-x)/(-x)
Now, we know that sec(x) is an even function, so sec(-x) = sec(x). Using this, we have ...
... g(-x) = sec(x)/(-x) = -sec(x)/x = -g(x)
The relation g(-x) = -g(x) is characeristic of an odd function, one that is symmetrical about the origin.
9514 1404 393
Answer:
Step-by-step explanation:
The decay factor is 1 -25% = 0.75 per hour, so the exponential equation can be written ...
r(t) = 1450·0.75^t . . . . . milligrams remaining after t hours
__
a) After 4 hours, the amount remaining is ...
r(4) = 1450·0.75^4 ≈ 458.79 . . . mg
About 459 mg will remain after 4 hours.
__
b) To find the time it takes before the amount remaining is less than 5 mg, we need to solve ...
r(t) < 5
1450·0.75^t < 5 . . . . use the function definition
0.75^t < 5/1450 . . . . divide by 1450
t·log(0.75) < log(1/290) . . . . . take logarithms (reduce fraction)
t > log(1/290)/log(0.75) . . . . . divide by the (negative) coefficient of t
t > 19.708
It will take about 20 hours for the amount of the drug remaining to be less than 5 mg.
