1a. Find the first derivative of y = 1/x
First, let's rewrite 1/x using a negative exponent:
y = 1/x
y = x−1
Next, find the derivative y' using the power rule:
y' = (-1) y−2
y' = −x−2
y' = −1/x2
1b. Find the second derivative of y = 1/x
Let's take the derivative of the result we found in part 1a (the second derivative is the derivative of the first derivative).
y' = −x−2
y'' = −(−2)x−3
y'' = 2x−3
y'' = 2/x3
2a. Find the first derivative of y = 1/x * (x2 − 3x)2
First, let's try and simplify the right side of the equation as much as possible.
We can factor an x from the expression inside the parentheses
y = 1/x * (x * (x − 3))2
Then, distribute the square over the terms in the outer parentheses
y = 1/x * (x)2 (x − 3)2
y = 1/x * x2 (x − 3)2
The first two terms, 1/x and x2 cancel to give:
y = x (x − 3)2
Next, foil the (x − 3)2 term
y = x * (x2 − 6x + 9)
Next, distribute the x over the terms in the parentheses
y = x3 − 6x2 + 9x
Now, apply the power rule to take the derivative
y' = 3x2 − (2)*6x + 9
y' = 3x2 − 12x + 9
2a. Find the first derivative of y = 1/x * (x2 − 3x)2
Let's take the derivative of the result we found in part 2a (the second derivative is the derivative of the first derivative).
y' = 3x2 − 12x + 9
y'' = (2)*3x − 12
y'' = 6x − 12