Suppose that z varies jointly with the cube of x and the square of y. Find the constant of proportionalityk if z=3600 when y=3 and x=5. Using the k from above write the variation equation in terms of x and y. Using the k from above find z given that x=12 and x=13.
Q. Suppose that z varies jointly with the cube of x and the square of y. Find the constant of proportionality k if z=3600 when y=3 and x=5. Using the k from above write the variation equation in terms of x and y. Using the k from above find z given that x=12 and x=13.
Identify general form: Identify the general form of joint variation.The general form of joint variation is z=k×xn×ym, where k is the constant of proportionality, n and m are the powers to which x and y are raised, respectively.In this case, since z varies jointly with the cube of x and the square of y, the equation becomes z=k×x3×y2.
Substitute values into equation: Substitute z=3600, y=3, and x=5 into the equation z=k×x3×y2.3600=k×53×32
Calculate x3 and y2: Calculate the values of x3 and y2.53=12532=9
Substitute calculated values: Substitute the calculated values back into the equation. 3600=k×125×9
Solve for constant: Solve the equation for the constant of proportionality, k.3600=k×1125k=11253600k=3.2
Write joint variation equation: Write the joint variation equation using the value of k.Substitute k=3.2 into z=k×x3×y2.The joint variation equation is z=3.2×x3×y2.
Find z with new values: Find z given that y=12 and x=13 using the joint variation equation.Substitute y=12 and x=13 into z=3.2×x3×y2.z=3.2×133×122
Calculate 133 and 122: Calculate the values of 133 and 122.133=2197122=144
Substitute values for z: Substitute the calculated values back into the equation to find z.z=3.2×2197×144
Perform multiplication: Perform the multiplication to find the value of z.z=3.2×316,608z=1,013,145.6
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