A model predicting the average temperature in a city during January 2012 is given by T(t) = t4 − 13t2 + 38, where t is the number of weeks that have passed since December 31, 2011, and T is the average temperature of the week in degrees Celsius. In which week will the average temperature be lower than 2°C?

(Hint: The first week of January translates to t = 0, and the week starts from January 1.)

January 1–7

January 8–14

January 15–21

January 22–28

Question

A model predicting the average temperature in a city during January 2012 is given by T(t) = t4 − 13t2 + 38, where t is the number of weeks that have passed since December 31, 2011, and T is the average temperature of the week in degrees Celsius. In which week will the average temperature be lower than 2°C?

(Hint: The first week of January translates to t = 0, and the week starts from January 1.)

    January 1–7

    January 8–14

    January 15–21

    January 22–28

anonymous · Answer

T(t)=t^4-13t^2+38

anonymous · Answer

0^4-13(0)^2+38?

campbell_st · Answer

why not set T(t) < 2 

and then solve the ineqality

$$2 < t^4 - 13t^2 + 38$$

and it looks like something that can be reduced to a quadratic

anonymous · Answer

t>3

campbell_st · Answer

an alternate method is to just substitute t = 0,t = 1 t = 2 etc....

campbell_st · Answer

and t = 3 makes sense

as when t = 2,  T(2) = 2

anonymous · Answer

so January 15–21

anonymous · Answer

????

anonymous · Answer

you dont give me no approval or nothing I got take my chances

campbell_st · Answer

well remember you started 1st week was t = 0    2nd week t = 1  3rd week t =2 and 4th week t = 3