Solutions to problems:
1. y = 8, -2
2. 5050
3. f'(x) = 3 * ln(2x^3) + 9
1. y^2 - 6y - 16 = 0
step 1: Add 16 over to the right side
y^2 - 6y - 16 = 0
+16 +16
y^2 - 6y = 16
step 2: Complete the Square by dividing -6 by 2 and then squaring the
quotient.
y^2 - 6y + (-6/2)^2 = 16 + (-6/2)^2
y^2 - 6y + 9 = 16 + 9
y^2 - 6y + 9 = 25
step 3: Change y^2 - 6y + 9 into the binomial expression (ax+b)^n where a,
b and n all represent integers
(y-3)^2 = 25
step 4: Square root both sides, remember when the right number is square
to include +/- in front of it.
_______ ___
V (y-3)^2 = +/- V 25
y - 3 = +/- 5
y = 3 +/- 5
________
| y = 8 , -2 |
|________|
2. The best way to approach this problem is to consider the numbers
between 0 and 100 as pairs.
For instance 0 + 100 = 100 , 1 + 99 = 100 , 2 + 98 = 100, etc...
All the way to 49 + 51 being the last pair and 50 stands alone.
This looks like:
(0 + 100) + (1 + 99) + (2 + 98) + ... + (49 + 51) + 50
There are in total 50 pairs that add up to 100 and then that lonesome 50 which is similar to saying:
____
50(100) + 50 = |5050|
|____|
* The famous mathematician Carl Gauss is credited when finding the solution
to this problem in elementary school in the 1700s, when assigned this for
busy work by the teacher. He completed the problem incredibly quickly too!
As such the formula now exist for the sum of any consecutive integers
which is:
S = [(n)(n+1)]/ 2
where S represents the sum and
n represents the number of consecutive integers. *
Note: This answer could also be derived from disregarding 0 since it adds no
value to the sum and pairing the numbers as such:
(1 + 100) + (2 + 99) + (3 + 98) + .... + (50 + 51)
there will still be 50 pairs of 101 which multiplies to 5050!
3. I will use f'(x) to represent the derivative... d/dx also works!
f(x) = 3x * ln(2x^3)
step 1: use CHAIN RULE to take derivative since it is two functions.
Note: ln(x)'s derivative is 1/x
Note: derivative power rule applies to 2x^3 function inside of ln
f'(x) = 3 * ln(2x^3)+ 3x * (6x^2)/(2x^3)
step 2: Simplify
f'(x) = 3 * ln(2x^3) + 3x * (3/x)
____________
f'(x) = |3 * ln(2x^3) + 9| , since x's cancel
|_____________|
Any questions, comments, or input about other problems you'd like to see feel free to post! I'll take all into consideration and do my best to post the completed work!
If you feel as though you or your child needs tutoring and don't want to be charged an outrageous fee, please contact me, Evan Lick, at lick.evan@gmail.com! I would love the opportunity to help and assist in all subjects of Mathematics!
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