Question

why does 3cos2x-2sin(x/3) never eqqual 5?

Answer 1

Hello

Answer 2

If that is true, than 3cos2x-2sin(x/3)=5 has no solutions, right?

Answer 3

First, we can put everything in terms of sin by using the identity
cos2x=1-2(sinx)^2

Answer 4

3(1-2(sinx)^2)-2sin(x/3)=5

Answer 5

3-6(sinx)^2-2sin(x/3)=5
3(sinx)^2+sin(x/3)=-1

Answer 6

Now, this gets a bit interesting here.

Answer 7

What is the minimum of (sinx)^2?

Answer 8

@KerriA

Answer 9

Hello?
Are you there?