Trial Q (1 Viewer)

[krypticlemonjuice]

Someone please explain how to do this question

 

[synthesisFR]

Is it A?

 

[hmim]

Is it A?

yeah, how’d you get it?

 

[synthesisFR]

okay move the two to the left but it doesn't matter
so u have to see if any solutions are equal to zero

if u look at the equation, its a periodic function since both terms have sin or cos
so then if it ever crosses the x axis it will do so forever

but they also limited the domain from 0 to 2pi
if u quickly check those two endpoints, u will see that

they are both at a max the final answer u get on the LHS is 1, which occurs at 0 and 2pi
but u don't know if it goes below the x axis

if u test x=pi/4 which is when they r both 1/sqrt2, u get like 2sqrt2-2 which is still greater than one
after that the values for each x go opposite to each other idk how to explain this bit but yeah it made sense it my head
or u can just quickly test the next value and u see that the functions value increases
so its always above the x axis and hence there is no solution

 

[Drongoski]

No solutions because:

The smallest each of the terms: can be is 1. Therefore the sum of these 2 terms cannot be less than 2. But this sum equals 2 only when each term equals 1 simultaneously. Each term equals 1 only when ; but this cannot happen simultaneously, e.g. when