The Function $f$ Is Shown Below. What Is The Value Of $\int_{-7}^4 F(x) \, Dx$? Write Your Answer In Simplest Form.

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Introduction


In this article, we will explore the function ff and calculate the value of its definite integral from βˆ’7-7 to 44. The function ff is given, and we will use various mathematical techniques to find the integral value.

The Function ff


The function ff is defined as:

f(x)={3x+2ifΒ x<βˆ’25βˆ’2xifΒ xβ‰₯βˆ’2f(x) = \begin{cases} 3x + 2 & \text{if } x < -2 \\ 5 - 2x & \text{if } x \geq -2 \end{cases}

Calculating the Integral


To calculate the integral of f(x)f(x) from βˆ’7-7 to 44, we need to break it down into two parts: the integral from βˆ’7-7 to βˆ’2-2 and the integral from βˆ’2-2 to 44.

Integral from βˆ’7-7 to βˆ’2-2


For the integral from βˆ’7-7 to βˆ’2-2, we use the function f(x)=3x+2f(x) = 3x + 2.

βˆ«βˆ’7βˆ’2f(x) dx=βˆ«βˆ’7βˆ’2(3x+2) dx\int_{-7}^{-2} f(x) \, dx = \int_{-7}^{-2} (3x + 2) \, dx

Using the power rule of integration, we get:

βˆ«βˆ’7βˆ’2(3x+2) dx=[3x22+2x]βˆ’7βˆ’2\int_{-7}^{-2} (3x + 2) \, dx = \left[ \frac{3x^2}{2} + 2x \right]_{-7}^{-2}

Evaluating the expression at the limits, we get:

[3x22+2x]βˆ’7βˆ’2=(3(βˆ’2)22+2(βˆ’2))βˆ’(3(βˆ’7)22+2(βˆ’7))\left[ \frac{3x^2}{2} + 2x \right]_{-7}^{-2} = \left( \frac{3(-2)^2}{2} + 2(-2) \right) - \left( \frac{3(-7)^2}{2} + 2(-7) \right)

Simplifying the expression, we get:

(3(βˆ’2)22+2(βˆ’2))βˆ’(3(βˆ’7)22+2(βˆ’7))=(122βˆ’4)βˆ’(1472βˆ’14)\left( \frac{3(-2)^2}{2} + 2(-2) \right) - \left( \frac{3(-7)^2}{2} + 2(-7) \right) = \left( \frac{12}{2} - 4 \right) - \left( \frac{147}{2} - 14 \right)

=(6βˆ’4)βˆ’(1472βˆ’14)= (6 - 4) - \left( \frac{147}{2} - 14 \right)

=2βˆ’(1472βˆ’14)= 2 - \left( \frac{147}{2} - 14 \right)

=2βˆ’1472+14= 2 - \frac{147}{2} + 14

=2βˆ’1472+282= 2 - \frac{147}{2} + \frac{28}{2}

=2βˆ’1192= 2 - \frac{119}{2}

=42βˆ’1192= \frac{4}{2} - \frac{119}{2}

=βˆ’1152= -\frac{115}{2}

Integral from βˆ’2-2 to 44


For the integral from βˆ’2-2 to 44, we use the function f(x)=5βˆ’2xf(x) = 5 - 2x.

βˆ«βˆ’24f(x) dx=βˆ«βˆ’24(5βˆ’2x) dx\int_{-2}^{4} f(x) \, dx = \int_{-2}^{4} (5 - 2x) \, dx

Using the power rule of integration, we get:

βˆ«βˆ’24(5βˆ’2x) dx=[5xβˆ’x2]βˆ’24\int_{-2}^{4} (5 - 2x) \, dx = \left[ 5x - x^2 \right]_{-2}^{4}

Evaluating the expression at the limits, we get:

[5xβˆ’x2]βˆ’24=(5(4)βˆ’(4)2)βˆ’(5(βˆ’2)βˆ’(βˆ’2)2)\left[ 5x - x^2 \right]_{-2}^{4} = \left( 5(4) - (4)^2 \right) - \left( 5(-2) - (-2)^2 \right)

Simplifying the expression, we get:

(5(4)βˆ’(4)2)βˆ’(5(βˆ’2)βˆ’(βˆ’2)2)=(20βˆ’16)βˆ’(βˆ’10βˆ’4)\left( 5(4) - (4)^2 \right) - \left( 5(-2) - (-2)^2 \right) = \left( 20 - 16 \right) - \left( -10 - 4 \right)

=(4)βˆ’(βˆ’14)= (4) - (-14)

=4+14= 4 + 14

=18= 18

Combining the Integrals


Now that we have calculated the two integrals separately, we can combine them to get the final answer.

βˆ«βˆ’74f(x) dx=βˆ«βˆ’7βˆ’2f(x) dx+βˆ«βˆ’24f(x) dx\int_{-7}^{4} f(x) \, dx = \int_{-7}^{-2} f(x) \, dx + \int_{-2}^{4} f(x) \, dx

=βˆ’1152+18= -\frac{115}{2} + 18

=βˆ’1152+362= -\frac{115}{2} + \frac{36}{2}

=βˆ’792= -\frac{79}{2}

The final answer is βˆ’792\boxed{-\frac{79}{2}}.

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Introduction


In our previous article, we explored the function ff and calculated the value of its definite integral from βˆ’7-7 to 44. In this article, we will answer some frequently asked questions related to the function ff and its integral value.

Q&A


Q: What is the function ff?

A: The function ff is defined as:

f(x)={3x+2ifΒ x<βˆ’25βˆ’2xifΒ xβ‰₯βˆ’2f(x) = \begin{cases} 3x + 2 & \text{if } x < -2 \\ 5 - 2x & \text{if } x \geq -2 \end{cases}

Q: How do I calculate the integral of f(x)f(x) from βˆ’7-7 to 44?

A: To calculate the integral of f(x)f(x) from βˆ’7-7 to 44, you need to break it down into two parts: the integral from βˆ’7-7 to βˆ’2-2 and the integral from βˆ’2-2 to 44. For the integral from βˆ’7-7 to βˆ’2-2, you use the function f(x)=3x+2f(x) = 3x + 2. For the integral from βˆ’2-2 to 44, you use the function f(x)=5βˆ’2xf(x) = 5 - 2x.

Q: What is the value of the integral from βˆ’7-7 to βˆ’2-2?

A: The value of the integral from βˆ’7-7 to βˆ’2-2 is:

βˆ«βˆ’7βˆ’2f(x) dx=βˆ’1152\int_{-7}^{-2} f(x) \, dx = -\frac{115}{2}

Q: What is the value of the integral from βˆ’2-2 to 44?

A: The value of the integral from βˆ’2-2 to 44 is:

βˆ«βˆ’24f(x) dx=18\int_{-2}^{4} f(x) \, dx = 18

Q: What is the final answer to the integral from βˆ’7-7 to 44?

A: The final answer to the integral from βˆ’7-7 to 44 is:

βˆ«βˆ’74f(x) dx=βˆ’792\int_{-7}^{4} f(x) \, dx = -\frac{79}{2}

Q: Can I use a calculator to calculate the integral?

A: Yes, you can use a calculator to calculate the integral. However, it's always a good idea to understand the underlying math and be able to calculate the integral by hand.

Q: What if I have a different function ff?

A: If you have a different function ff, you will need to follow the same steps to calculate the integral. However, the specific steps and calculations will depend on the function ff.

Conclusion


In this article, we answered some frequently asked questions related to the function ff and its integral value. We hope that this article has been helpful in understanding the function ff and its integral value.

Additional Resources


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