Answer:
this is tricky
Step-by-step explanation:
Answer:
Step-by-step explanation:
Brain correctly use a method of completing the square to solve the equation:
His First Step is to: Take the Constant Term to the Right Hand Side
The Next Step Would be to:
- Divide the Coefficient of x by 2
- Square It
- Add it to both Sides
In this case, the Coefficient of x = 7
- Divided by 2 =
- Squaring It, we have:
It is this number that is added to both sides in the manner below:
Taking the derivative of 7 times secant of x^3:
We take out 7 as a constant focus on secant (x^3)
To take the derivative, we use the chain rule, taking the derivative of the inside, bringing it out, and then the derivative of the original function. For example:
The derivative of x^3 is 3x^2, and the derivative of secant is tan(x) and sec(x).
Knowing this: secant (x^3) becomes tan(x^3) * sec(x^3) * 3x^2. We transform tan(x^3) into sin(x^3)/cos(x^3) since tan(x) = sin(x)/cos(x). Then secant(x^3) becomes 1/cos(x^3) since the secant is the reciprocal of the cosine.
We then multiply everything together to simplify:
sin(x^3) * 3x^2/ cos(x^3) * cos(x^3) becomes
3x^2 * sin(x^3)/(cos(x^3))^2
and multiplying the constant 7 from the beginning:
7 * 3x^2 = 21x^2, so...
our derivative is 21x^2 * sin(x^3)/(cos(x^3))^2
$91/ 7 = $13 per dog
$117/$13 = 9 dogs
He washed 9 dogs
