Determine the Domain of: √(3x²+7)/12

Question

Look at the following function:

3x2+712 \frac{\sqrt{3x^2+7}}{12}

What is the domain of the function?

Video Solution

Solution Steps

00:00 Does the function have a domain? And if so, what is it?
00:04 The domain in the denominator is to avoid division by 0
00:07 Therefore, from the denominator's perspective there is no domain restriction, let's check the numerator
00:12 A root must be for a positive number
00:15 Let's isolate X
00:25 The square of any number is always positive
00:33 Therefore there is no solution that makes the root negative
00:39 Thus the function exists for all X, and this is the solution to the question

Step-by-Step Solution

To find the domain of the function 3x2+712 \frac{\sqrt{3x^2+7}}{12} , we must ensure that the function is defined for all real numbers.

Step 1: Evaluate the expression under the square root, 3x2+7 3x^2 + 7 , which must be non-negative. Since it's a quadratic expression in the form of ax2+b ax^2 + b , compute for any potential zero or negative range.

Step 2: Notice that 3x2+70 3x^2 + 7 \geq 0 for all x x because 3x20 3x^2 \geq 0 for any real number x x and adding 7 makes this entire expression always positive (i.e., tends upwards away from zero).

Step 3: As the denominator 12 12 is a positive constant, it imposes no additional restrictions on the domain. Thus, the function is defined wherever the numerator is defined.

Conclusion: Since there's no x x that makes 3x2+7<0 3x^2 + 7 < 0 , the function is defined for all real numbers.

This means the domain of the function is all real numbers, confirmed by choice number 1: All real numbers \text{All real numbers} .

Answer

All real numbers