Applying implicit differentiation, it is found that dy/dt when y=π/4 is of:
a-) -√2 / 2.
<h3>What is implicit differentiation?</h3>
Implicit differentiation is when we find the derivative of a function relative to a variable that is not in the definition of the function.
In this problem, the function is:
xcos(y) = 2.
The derivative is relative to t, applying the product rule, as follows:
![\cos{y}\frac{dx}{dt} - x\sin{y}\frac{dy}{dt} = 0](https://tex.z-dn.net/?f=%5Ccos%7By%7D%5Cfrac%7Bdx%7D%7Bdt%7D%20-%20x%5Csin%7By%7D%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%200)
![\frac{dy}{dt} = \frac{\cos{y}\frac{dx}{dt}}{x\sin{y}}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%20%5Cfrac%7B%5Ccos%7By%7D%5Cfrac%7Bdx%7D%7Bdt%7D%7D%7Bx%5Csin%7By%7D%7D)
Since dx/dt=−2, we have that:
![\frac{dy}{dt} = -2\frac{\cos{y}}{x\sin{y}}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%20-2%5Cfrac%7B%5Ccos%7By%7D%7D%7Bx%5Csin%7By%7D%7D)
When y = π/4, x is given by:
xcos(y) = 2.
![x = \frac{2}{\cos{\frac{\pi}{4}}} = \frac{2}{\frac{\sqrt{2}}{2}} = \frac{4}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = 2\sqrt{2}](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%7B2%7D%7B%5Ccos%7B%5Cfrac%7B%5Cpi%7D%7B4%7D%7D%7D%20%3D%20%5Cfrac%7B2%7D%7B%5Cfrac%7B%5Csqrt%7B2%7D%7D%7B2%7D%7D%20%3D%20%5Cfrac%7B4%7D%7B%5Csqrt%7B2%7D%7D%20%5Ctimes%20%5Cfrac%7B%5Csqrt%7B2%7D%7D%7B%5Csqrt%7B2%7D%7D%20%3D%202%5Csqrt%7B2%7D)
Hence:
![\frac{dy}{dt} = -2\frac{\cos{y}}{x\sin{y}}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%20-2%5Cfrac%7B%5Ccos%7By%7D%7D%7Bx%5Csin%7By%7D%7D)
![\frac{dy}{dt} = -\frac{1}{\sqrt{2}}\cot{y}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%20-%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%7D%5Ccot%7By%7D)
Since cot(pi/4) = 1, we have that:
![\frac{dy}{dt} = -\frac{1}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = -\frac{\sqrt{2}}{2}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdt%7D%20%3D%20-%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%7D%20%5Ctimes%20%5Cfrac%7B%5Csqrt%7B2%7D%7D%7B%5Csqrt%7B2%7D%7D%20%3D%20-%5Cfrac%7B%5Csqrt%7B2%7D%7D%7B2%7D)
Which means that option a is correct.
More can be learned about implicit differentiation at brainly.com/question/25608353
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Answer:
2x + 1y =< 300
x + y =>150 units
y <= 2x
Step-by-step explanation:
Let x and y be the numbers of corndogs and shakes that will be sold.
<u>1.</u> The total cost of making these items is given by the sum of:
(x)(RM2) + (y)(RM1)
A total of RM300 is allocated for the cost of these items, so:
2x + 1y =< 300 [Units are RM)
<u>2.</u> Sales are expected to exceed 150 units, in total. This means:
x + y =>150 units
<u>3.</u> Sales for the shakes is less than 2 times that of the corndogs:
y <= 2x
The sine function has a minimum value of -1, so f(x) = 4sin( ) -1 will have a minimum value of -5.
g(x) obviously has a minimum value of -3.
h(x) has a squared term that cannot be negative, so its minimum value is +4.
f(x) has the smallest minimum value.