Question

-2 cos(x)

is concave down on what interval pls...i have tried all i know

Answer 1

make sure you are asking the right question :)

Answer 2

-2cos (x) is already in its second derivative form

Answer 3

i have got the points of inflection is pi/2 and 3pi/2

Answer 4

then this came from 2cos(x) which is the same concavity and periodicty of cos(x)

Answer 5

its concave up on (pi/2 , 3pi/2)

but for the life of me cant get the down interval