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burhan101
 2 years ago
Determine the derivative, all the critical numbers and the intervals of increase and decrease
y=5x²+20x+2
burhan101
 2 years ago
Determine the derivative, all the critical numbers and the intervals of increase and decrease y=5x²+20x+2

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burhan101
 2 years ago
Best ResponseYou've already chosen the best response.0\[\huge y'=10x+20\] \[\huge 0=10x+20\] \[x=2\]

burhan101
 2 years ago
Best ResponseYou've already chosen the best response.0i get : intervals of increase x<2 intervals of decrease x>2 but the answer key says the opposite

Abhishek619
 2 years ago
Best ResponseYou've already chosen the best response.0when \[y \prime >0, \] then increasing.

burhan101
 2 years ago
Best ResponseYou've already chosen the best response.0what's in intervals of increase / decrease tho?

koymoi
 2 years ago
Best ResponseYou've already chosen the best response.0I got the same answer as you @burhan101 intervals of increase x<2 intervals of decrease x>2

Abhishek619
 2 years ago
Best ResponseYou've already chosen the best response.0x>2 it decreases x<2 it increases.

johnweldon1993
 2 years ago
Best ResponseYou've already chosen the best response.0Right...I as well @koymoi ...I think maybe your answer key is wrong @burhan101

burhan101
 2 years ago
Best ResponseYou've already chosen the best response.0think the answer key's wrong then ?

burhan101
 2 years ago
Best ResponseYou've already chosen the best response.0yeah, i thought it was a fairly straight forward question

dan815
 2 years ago
Best ResponseYou've already chosen the best response.0graph it and ull know for sure

dan815
 2 years ago
Best ResponseYou've already chosen the best response.0oh oops that shud be + when i multiplied by 5

genius12
 2 years ago
Best ResponseYou've already chosen the best response.1@burhan101 u don't need calculus to find intervals of increase/decrease. This is a parabola with a negative leading coefficient so it opens down. Using b/2a we get b/2a = 2, which is the xcoordinate of the vertex of the parabola. Since it opens down, function is increasing on \(\bf (\infty,2)\) and decreasing on \(\bf (2,\infty)\)
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