Area between two curves

Question

y=xsqrt(x-2) , y=-xsqrt(x-2) , x=4 

 

In the answer booklet it says y² = x² (x-2) . I dont understand why you are squaring the y ? 

Answer 1

Hi Alex,

 

Take a look at the following page: https://www.desmos.com/calculator/de42wunlpa

 

Highlight the graph of y² = x² (x-2). You will see it is identical to the combination of the two functions containing the square root symbols. Not sure exactly how the answer booklet used the y² = ....

 

Notice I found the area between the two curves and x=4, by doubling the area between for one of the regions.