Question

Please help

Find all solutions in the interval [0, 2π).

(sin x)(cos x) = 0

Answer 1

just like with a factored quadratic (x+1)(x-2)=0
you look for when the individual parentheses are zero. so how would you do that here?

Answer 2

either sinx=0 or cosx=0 or both
sinx=0 i.e. x=2n(pi) and cosx=0 i.e. (2n+1)(pi/2)
so [0.2pi) are 1in sine x=0&1 in cos when x=pi/2
so total 2
:)

Answer 3

I won't lie I am completely lost and have no idea what either of you are talking about. :P I'm sorry.

The possible answers are
pi/2 , pi
0 , pi/2 , pi , 3pi/2
pi , 3pi/2
0 , 3p/2

Thanks for answering by the way. But I still don't understand.

Answer 4

@qwertyuu let me help u do you know the graph of sinx and cos x

Answer 5

1) what do you know about the sin(x) as a function of x? can you sketch it? draw it?
2) same thing with cos(x).
most importantly, do you know for want angles both these functions are zero?

Answer 6

http://math.usask.ca/emr/images/sinx.gif
http://intmstat.com/trigonometric-graphs/cos.gif
http://www.youtube.com/watch?v=FUMpGuLIQ5M&feature=player_embedded

Answer 7

first check them out and then tell me when its amplitude becomes zero:)