State when f(x) is increasing , decreasing , concave up , concave down .

f(x) = sec x. tan x

⇔ f(x) = 1/cosx . cosx/sinx

⇔ f(x) = sin x

+) when f(x) is increasing => sin x increases

=> x will increase

+) f(x) is decreasing => x will decrease

+) f(x) is concave up => x ∈ (-pi/2; 0)

+) f(x) concave down => x ∈ (0; pi/2)

Step-by-step explanation:

the best buy, is the 4- kilogram bag of lollipops for $18.40.

step-by-step explanation:

i found my answer by dividing the cost of each bag by their respective weights.

14.88 divided by 2 = 7.44

17.29 divided by 3 = 5.77

18.4 divided by 4 = 4.6

24.4 divided by 5 = 4.88

by this, i found that the 4 kilo bag is the best buy.