Integration question

[Adi]

Hey guys I'm working on this and I just learnt about integration this week. Can somebody please tell me if what I've done is correct or if Ive made a mistake?

 

[Steven G]

The first part looks fine.
In the 2nd part the fourth line from the bottom has a wrong sign. Did you answer all part of b?
What about part c?

Why on earth would you use the quotient rule to find that derivative?

 

[Adi]

The first part looks fine.
In the 2nd part the fourth line from the bottom has a wrong sign. Did you answer all part of b?
What about part c?

Why on earth would you use the quotient rule to find that derivative?

Oh thanks so much Jomo you have saved me. I used the quotient rule because it was a fraction. I'm a noob to the rules. Which rule would you recommend I use?

 

[Adi]

All good I've solved all of part b. Got Q^2 for the derivative. No idea how to go about part c though. Anybody able to help?

 

[Adi]

I'm really lost as to waht pa

All good I've solved all of part b. Got Q^2 for the derivative. No idea how to go about part c though. Anybody able to help?

Even a more clear wording of what the question is asking me to do would help

 

[Deleted member 4993]

I'm really lost as to waht pa

Even a more clear wording of what the question is asking me to do would help

What is the value of P when Q>100 (for the given demand function)?

 

[Steven G]

Oh thanks so much Jomo you have saved me. I used the quotient rule because it was a fraction. I'm a noob to the rules. Which rule would you recommend I use?

If y =kf(x), then y'=k*f'(x). Example: y= 3x^2, then y'= 3*2x=6x. I suspect that you knew that one. Just note that y= x³/7 = (1/7)x³. So y' = (1/7)*3x² = (3/7)x². No quotient rule!

Only use the quotient if both the numerator and denominators are NOT constants.