Given the graph of y = cos θ on the interval 0 ≤ θ ≤ 2π, for which value of θ does y have upward concavity?
a. θ = 0

b. θ = 1

c.θ = 2

d.none of these

I am pretty sure that it is d

Question

Given the graph of y = cos θ on the interval 0 ≤ θ ≤ 2π, for which value of θ does y have upward concavity? 
a. θ = 0
		
b. θ = 1
		
c.θ = 2
		
d.none of these

I am pretty sure that it is d

anonymous · Answer

Yep. If you understand derivatives yet then you can find the 2nd derivative of y which is y'' and you'll get y''=-cos(x). So When you plug in values for the second derivative a little rule is that when y'' is positive the original function y is concave up. When you plug in values for the second derivative and find y'' to be negative then the original function y is concave down. So for all your answers you'll always get a negative second derivative.