Question

differentiate mod cosx

Answer 1

you know modulus concept
it means always positive
i.e mod cosx ={cosx when x €[-pi/2, pi/2] take this period because cosx is periodic functions
=-cosx when x €(pi/2,3pi/2) also take this period

now differentiate

dy/dx={-sinx when x €[-pi/2, pi/2]
{ sinx when x €(pi/2,3pi/2)