MATHS EXT1 (1 Viewer)

[Farhanthestudent005]

Will appreciate if helped. Thank you

 

[specificagent1]

do you have the answers?

 

[jimmysmith560]

do you have the answers?

614 radios per week.

 

[specificagent1]

614 radios per week.

Thanks for confirming that.


So we are going to approach this question by firstly differentiating both sides in respect to time to find a rate.

N = x^2 +7x
d/dt N = d/dt (x^2 +7x)
dn/dt = (2x + 7) . dx/dt (partial differentiation)

We are given that the amount of workers (x) is decreasing by 2 every week (time = t) therefore dx/dt = -2

What is the rate at which the radio (N) is changing over time (t) when there are 150 workers? (x = 150)

dn/dt = (2(150) +7) . -2
dn/dt = 307 . -2
dn/dt = -614

Therefore the rate is decreasing by 614 per week

 

[CM_Tutor]

dn/dt = (2x + 7) . dx/dt (partial differentiation)

One little point about this line. The process that you are using here is called implicit differentiation. The term "partial differentiation" has a different meaning that is not included in the HSC syllabus but is in first year Uni maths.