Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

The base of a solid is the region enclosed by the graphs of 
y=sin(x) and 
y=4-sqrtx, between 
x=2 and 
x=7.
Cross sections of the solid perpendicular to the 
x-axis are rectangles whose height is 
2x.
Which one of the definite integrals gives the volume of the solid?
Choose 1 answer:
(A) 
int_(2)^(7)[sin(x)+sqrtx-4]*2xdx
(B) 
int_(2)^(7)[sin^(2)(x)-(4-sqrtx)^(2)]dx
(C) 
int_(2)^(7)[4-sqrtx-sin(x)]*2xdx
(D) 
int_(2)^(7)[(4-sqrtx)^(2)-sin^(2)(x)]dx

The base of a solid is the region enclosed by the graphs of y=sin(x) y=\sin (x) and y=4x y=4-\sqrt{x} , between x=2 x=2 and x=7 x=7 .\newlineCross sections of the solid perpendicular to the x x -axis are rectangles whose height is 2x 2 x .\newlineWhich one of the definite integrals gives the volume of the solid?\newlineChoose 11 answer:\newline(A) 27[sin(x)+x4]2xdx \int_{2}^{7}[\sin (x)+\sqrt{x}-4] \cdot 2 x d x \newline(B) 27[sin2(x)(4x)2]dx \int_{2}^{7}\left[\sin ^{2}(x)-(4-\sqrt{x})^{2}\right] d x \newline(C) 27[4xsin(x)]2xdx \int_{2}^{7}[4-\sqrt{x}-\sin (x)] \cdot 2 x d x \newline(D) 27[(4x)2sin2(x)]dx \int_{2}^{7}\left[(4-\sqrt{x})^{2}-\sin ^{2}(x)\right] d x

Full solution

Q. The base of a solid is the region enclosed by the graphs of y=sin(x) y=\sin (x) and y=4x y=4-\sqrt{x} , between x=2 x=2 and x=7 x=7 .\newlineCross sections of the solid perpendicular to the x x -axis are rectangles whose height is 2x 2 x .\newlineWhich one of the definite integrals gives the volume of the solid?\newlineChoose 11 answer:\newline(A) 27[sin(x)+x4]2xdx \int_{2}^{7}[\sin (x)+\sqrt{x}-4] \cdot 2 x d x \newline(B) 27[sin2(x)(4x)2]dx \int_{2}^{7}\left[\sin ^{2}(x)-(4-\sqrt{x})^{2}\right] d x \newline(C) 27[4xsin(x)]2xdx \int_{2}^{7}[4-\sqrt{x}-\sin (x)] \cdot 2 x d x \newline(D) 27[(4x)2sin2(x)]dx \int_{2}^{7}\left[(4-\sqrt{x})^{2}-\sin ^{2}(x)\right] d x
  1. Cross-Sectional Area Calculation: The volume of a solid with known cross-sectional area perpendicular to the xx-axis can be found by integrating the area of the cross-sections along the xx-axis. The area of each rectangular cross-section is given by the difference in the yy-values of the two functions (the height of the rectangle) times the given height of the rectangle (2x2x in this case). Therefore, the area A(x)A(x) of a cross-section at a point xx is A(x)=(upper functionlower function)×heightA(x) = (\text{upper function} - \text{lower function}) \times \text{height}. The upper function is y=4xy = 4 - \sqrt{x}, and the lower function is y=sin(x)y = \sin(x). So, A(x)=(4xsin(x))×2xA(x) = (4 - \sqrt{x} - \sin(x)) \times 2x.
  2. Setting up the Integral: We need to set up the integral of A(x)A(x) from x=2x = 2 to x=7x = 7 to find the volume. The integral that represents the volume VV is V=27A(x)dx=27(4xsin(x))2xdxV = \int_{2}^{7} A(x) \, dx = \int_{2}^{7} (4 - \sqrt{x} - \sin(x)) \cdot 2x \, dx.
  3. Comparison with Options: Comparing the integral we found with the options given, we see that option (C) matches our integral: (C)27[4xsin(x)]2xdx(C) \int_{2}^{7} [4 - \sqrt{x} - \sin(x)] \cdot 2x \, dx.

More problems from Evaluate definite integrals using the chain rule