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In Mathematics / High School | 2025-07-03

Let f(x, y) = 5x² - sin(7x - 6y). Now, assume that x and y are functions of u and v, given by:

x(u, v) = 6u - 4v², y(u, v) = 3u² - v.

Consider the composite function f(x(u, v), y(u, v)). What is the value of this function at (u, v) = (-1, 1)?

Asked by SopaMaru7292

Answer (2)

The value of the composite function f ( x ( u , v ) , y ( u , v )) at the point ( u , v ) = ( āˆ’ 1 , 1 ) is approximately 500.9903 . This is calculated by first determining x and y using the given functions and then substituting these into f ( x , y ) . The final result is derived from evaluating the sine function involved in the formula.
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Answered by Anonymous | 2025-07-04

To solve the problem, we need to find the value of the composite function f ( x ( u , v ) , y ( u , v )) at ( u , v ) = ( āˆ’ 1 , 1 ) .
First, recall the given function: f ( x , y ) = 5 x 2 āˆ’ sin ( 7 x āˆ’ 6 y )
Additionally, we have: x ( u , v ) = 6 u āˆ’ 4 v 2 y ( u , v ) = 3 u 2 āˆ’ v
Now, let's find the specific values for x and y when u = āˆ’ 1 and v = 1 :

Calculate x ( āˆ’ 1 , 1 ) : x ( āˆ’ 1 , 1 ) = 6 ( āˆ’ 1 ) āˆ’ 4 ( 1 ) 2 = āˆ’ 6 āˆ’ 4 = āˆ’ 10

Calculate y ( āˆ’ 1 , 1 ) : y ( āˆ’ 1 , 1 ) = 3 ( āˆ’ 1 ) 2 āˆ’ 1 = 3 ( 1 ) āˆ’ 1 = 2


Now, we have x = āˆ’ 10 and y = 2 . Substitute these values into the function f ( x , y ) :

Evaluate f ( āˆ’ 10 , 2 ) : f ( āˆ’ 10 , 2 ) = 5 ( āˆ’ 10 ) 2 āˆ’ sin ( 7 ( āˆ’ 10 ) āˆ’ 6 ( 2 )) Simplify further: = 5 ( 100 ) āˆ’ sin ( āˆ’ 70 āˆ’ 12 ) = 500 āˆ’ sin ( āˆ’ 82 )

Simplify the sine term: sin ( āˆ’ 82 ) = āˆ’ sin ( 82 ) because sine is an odd function. Therefore, we have: 500 + sin ( 82 )


Without a calculator, the exact value of sin ( 82 ) in terms of simple numbers cannot be further simplified. Thus, the value of the function is:
f ( āˆ’ 10 , 2 ) ā‰ˆ 500 + sin ( 82 )
In summary, the value of the composite function f ( x ( u , v ) , y ( u , v )) at ( u , v ) = ( āˆ’ 1 , 1 ) is 500 + sin ( 82 ) .

Answered by SophiaElizab | 2025-07-07