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)
First we have to get x by itself, so we multiply two on each side,
then we get 5x=660/4, I like to simplify here, so I would change it to 5x=165, then we divide each side by 5
x=33
:)
Answer:
B. Beth's age is 18 years, and Sally's age is 42 years.
Step-by-step explanation:
You can solve this question in a couple of different ways. First, you can use process of elimination. You know that Sally is older than Beth because she has to be 3 times older 6 years ago, so you can get rid of options C and D because they both show Beth as being older. Now you only have A and B, and you can use a different process. Now from just looking at it, you can tell that A actually already shows Sally as 3 times Beth's age, 15 * 3 = 45. If you go to B, you can go ahead and subtract 6 from 18 (Beth's age) which will give you 12, and then multiply that by 3 to get 36. Now if you take 42 (Sally's age) and subtract 6 from it as well, you will get 36. This means that is lines up. To simplify, you are subtracting 6 from both 18 and 42, and then you are multiplying the lower number by 3 to see if it gets to the bigger number.
Hope this helped ^-^
First, convert cm to inches.
50/2.54 is roughly 19.69
There are 12 inches in a foot, so divide the 19.69 by 12.
19.69/12 is roughly 1.64
So the answer is C
Answer:
9 x 7 = 63 is cost of 9 people
3 x 9
6 x 8
8 x 8
9 x 7
