EG = 24 ( solution is attached below)
If you wish to<u> mentally estimate</u> the <u>total cost</u> of items, <u>rounding </u>off the items to the<u> nearest half dollar</u>, then you have to consider all five items separately.
Five items cost $1.85, $.98, $3.49, $9.78, and $6.18.
1. $1.85≈$2;
2. $0.98≈$1;
3. $3.49≈$3.50;
4. $9.78≈$10;
5. $6.18≈$6.
Then the total cost is
$2 + $1 + $3.50 + $10 + $6 =$22.50.
Answer: correct choice is C
10+18=28
17+11=28
OR
2x=28 where x=14
4x where x=7
Recall that
d/dx sech(x) = - sech(x) tanh(x)
d/dx tan⁻¹(x) = 1/(1 + x²)
Then by the chain rule,
dy/dx = - sech(x) tanh(x) / (1 + x²)
