Math Question?

Question

Solve Cos2A=0 on the internval 0 less than or equal to A less than or equal to 2 pi.
please

Answer 1

First we establish that girls require time and money. So girls equal time(t) times money(m)

And as we know, time is money t = m

So now girls equals money squared girls = m^2

And because money is 'the root of all evil'

Girls equals 'the root of all evil' squared

So we are forced to conclude that Girls are evil

Answer 2

cos 2A = 2 cos^2(A) - 1

So

2 cos^2(A) - 1 = 0

2 cos^2(A) = 1

cos^2(A) = 1 /2

cos(A) = +-sqrt(1 /2)

So the possible answers are pi/4 3pi/4 5pi/4 7pi/4 but we have to check and make sure they all work since we took the sqrt of each side.

Cos 2(pi/4) = Cos pi/2 = 0

Cos 2(3pi/4) = Cos 3pi/2 = 0

Cos 2(5pi/4) = Cos 5pi/2 = 0

Cos 2(7pi/4) = Cos 7pi/2 = 0

Everything is all good :)

Answer 3

that's two hard for me!!!!