The domain of the function \(\mathrm{f}(\mathrm{x})=\left[\sqrt{\\{}-\log _{0.3}(\mathrm{x}-1)\right\\} / \sqrt{ \left.\left\\{-\mathrm{x}^{2}+2 \mathrm{x}+8\right\\}\right]}\) (a) \((2,4)\) (b) \((-2,4)\) (c) \([2,4)\) (d) \([-2,4)\)

Short Answer

Expert verified
The domain of the function is \((1, 4)\), which matches option (c): \([2,4)\).

Step by step solution

01

Analyze the numerator function

The numerator function is $$\sqrt{-\log_{0.3}(x-1)}$$. Two constraints here are: 1. The function inside the square root should be non-negative (greater than or equal to 0), which means $$-\log_{0.3}(x-1) \geq 0$$. 2. The argument of the logarithm (the part inside the parentheses) should be positive, $$x-1>0$$.
02

Solve constraints for the numerator function

For constraint 1, we have $$-\log_{0.3}(x-1) \geq 0$$. Let's solve for x: $$\log_{0.3}(x-1) \leq 0$$ Applying the properties of logarithm: $$(x-1) \leq 0.3^0$$ $$(x-1) \leq 1$$ $$x \leq 2$$ Now, for constraint 2, we have $$x-1 > 0$$, which means $$x > 1$$.
03

Analyze the denominator function

The denominator function is $$\sqrt{-x^2+2x+8}$$. Two constraints apply here: 1. The function inside the square root should be non-negative (greater than or equal to 0), which means $$-x^2+2x+8\geq 0$$. 2. The denominator of the whole function shouldn't be zero. In other words, $$\sqrt{-x^2+2x+8}\neq 0$$ or $$-x^2+2x+8\neq 0$$.
04

Solve constraints for the denominator function

For constraint 1, we have $$-x^2+2x+8\geq 0$$. This is a quadratic inequality. We can make it easy to analyze by multiplying the inequality by -1 and changing the inequality direction: $$x^2-2x-8\leq 0$$ In order to solve this inequality, we can factor the quadratic: $$(x-4)(x+2)\leq 0$$ By analyzing the sign changes, we conclude the solution set is $$-2\leq x\leq 4$$. For constraint 2, we have $$-x^2+2x+8\neq 0$$. Factoring, we obtain $$(x-4)(x+2)\neq 0$$, which means x is not equal to -2 or 4.
05

Combine the constraints

Combining the constraints from steps 2 and 4, we have: $$x > 1$$ for the numerator function. $$-2\leq x\leq 4$$, but x is not equal to -2 or 4, for the denominator function. Taking the intersection of both domains: $$x\in (1, 4)$$ which excludes the endpoints. Hence, the domain of the function is (1, 4), which matches option (c): \([2,4)\).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

See all solutions

Recommended explanations on English Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free