Continuity Functions Ef368C
1. We are asked to determine if the function $$g(x) = \frac{7x^2}{10 + 2x}$$ is continuous on various intervals.
2. Recall that a rational function is continuous everywhere its denominator is not zero.
3. Find where the denominator is zero:
$$10 + 2x = 0 \implies 2x = -10 \implies x = -5$$
4. So, $$g(x)$$ is continuous everywhere except at $$x = -5$$.
5. Now check each interval:
- a) $$(-6, 6)$$ includes $$-5$$, so $$g(x)$$ is not continuous on $$(-6, 6)$$.
- b) $$[-10, 0]$$ includes $$-5$$, so $$g(x)$$ is not continuous on $$[-10, 0]$$.
- c) $$(-\infty, -5)$$ does not include $$-5$$ (endpoint not included), so $$g(x)$$ is continuous on $$(-\infty, -5)$$.
- d) $$[-10, 20)$$ includes $$-5$$, so $$g(x)$$ is not continuous on $$[-10, 20)$$.
6. Therefore, $$x \neq -5$$ for continuity.
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7. Next, determine if $$m(x) = \sqrt{4 - x}$$ is continuous on given intervals.
8. The square root function is continuous on its domain, which requires the radicand to be non-negative:
$$4 - x \geq 0 \implies x \leq 4$$
9. So, $$m(x)$$ is continuous for all $$x \leq 4$$.
10. Check each interval:
- a) $$(0, 5)$$ includes values greater than 4, so $$m(x)$$ is not continuous on $$(0, 5)$$.
- b) $$[-6, 2]$$ is entirely less than or equal to 4, so $$m(x)$$ is continuous on $$[-6, 2]$$.
- c) $$[3, 9)$$ includes values greater than 4, so $$m(x)$$ is not continuous on $$[3, 9)$$.
- d) $$(-\infty, 4)$$ is within the domain, so $$m(x)$$ is continuous on $$(-\infty, 4)$$.
11. Therefore, $$x \neq 4$$ for continuity.
Final answers:
- For $$g(x)$$, discontinuous at $$x = -5$$.
- For $$m(x)$$, discontinuous at $$x = 4$$.