Sovi.AI - AI Math Tutor

Scan to solve math questions

QUESTION IMAGE

use your calculator to find the gradient of the graph of $y = \\frac{3x…

Question

use your calculator to find the gradient of the graph of $y = \frac{3x - 7}{\sqrt{11 - 3x}}$ at $x = 3$.
give your answer as a decimal, rounded to 3 significant figures.

Explanation:

Step1: Use the quotient rule

The quotient rule states that if \(y = \frac{u}{v}\), then \(y^\prime=\frac{u^\prime v - uv^\prime}{v^{2}}\). Let \(u=\sqrt{11 - 3x}=(11 - 3x)^{\frac{1}{2}}\) and \(v = 3x-7\).
First, find \(u^\prime\) and \(v^\prime\).
Using the chain rule, if \(u=(11 - 3x)^{\frac{1}{2}}\), then \(u^\prime=\frac{1}{2}(11 - 3x)^{-\frac{1}{2}}\times(- 3)=-\frac{3}{2\sqrt{11 - 3x}}\).
And \(v^\prime = 3\).

Step2: Apply the quotient rule

$$ LATEXBLOCK0 $$

Substitute \(x = 3\) into the derivative.
When \(x = 3\), \(u=\sqrt{11-3\times3}=\sqrt{2}\), \(v=3\times3 - 7 = 2\), \(u^\prime=-\frac{3}{2\sqrt{2}}\), \(v^\prime = 3\).

$$ LATEXBLOCK1 $$

Answer:

\(-2.12\)