1. ## Derivative of function- tangent/normal

$\displaystyle y = \frac{3x+4}{x-1}$

a. Determine all values for $\displaystyle x$ for which $\displaystyle \frac{dy}{dx}$ exists.

b. Find an expression for $\displaystyle \frac{dy}{dx}$.

Here are my answers..are they correct?

a. All real numbers not equal to 1

b. $\displaystyle \frac{-5}{(x-1)^2}$

2. Originally Posted by live_laugh_luv27
$\displaystyle y = \frac{3x+4}{x-1}$

a. Determine all values for $\displaystyle x$ for which $\displaystyle \frac{dy}{dx}$ exists.

b. Find an expression for $\displaystyle \frac{dy}{dx}$.

Here are my answers..are they correct?

a. All real numbers not equal to 1

b. $\displaystyle \frac{-5}{(x-1)^2}$

a) Correct.

b) Incorrect. Should actually be $\displaystyle -\frac{7}{(x - 1)^2}$.

3. ok, thanks.

1) Find line tangent to the curve at $\displaystyle (8,4)$
2) Find line normal to the curve at $\displaystyle (8,4)$and determine the cooridinates of another point where this line intersects the graph.
1) $\displaystyle y-4=-\frac{7}{64}(x-8)$
2) $\displaystyle y-4=\frac{64}{7}(x-8)$