I need help with higher maths homework please!

[pauliwauli2]

if you have an equation such as:

sinxcosx = 0

how do you work out what x is? i know it's easy and i've done it before, it's just gone out of my head!

thank you

[kempie]

Any number multiplied by zero will give a result of zero.

Therefore either sin x = 0 or cos x = 0
and since sin 0� and cos 90� = 0
then x = 0� or 90�

Thus
sin 0� x cos 0� = 0 x 1 = 0
sin 90� x cos 90� = 1 x 0 = 0

[gen2]

Those are not the only solutions.

Yes, sin(0�) =0, but so does sin((N*180)� )
and cos(90�)=0, but so does cos ((90+N*180)� )
for all integers of N

so there are an infinite number of solutions to this equation rather than the two stated so far.

[pauliwauli2]

thanks! sorted ;)