Help needed for SEC 3 additional maths

Solve the following equations for 0deg =< (x) >= 360deg
1) cos 2(x) cos (x) = sin 4(x) sin (x)
2) cos (x) + cos 2(x) + cos 3(x) + cos 4(x) = 0

ans: 1) 30deg 45deg 90deg 135deg 150deg 210deg 225deg 270deg 315deg 330deg
2) 36deg 90deg 108deg 180deg 252deg 270deg 324deg

Hi all

can someone provide opinion on this matter.
For a transverse wave travelling to the right, at a particular instant, what is the speed of the particles at the crest, the centre position and at the trough when compare to each other? Which is faster -- Vcrest, Vcentre & Vtrough?
Thank you

My parents brought me recently to the Adam Khoo talk and I was quite impress with the right brain technique they use to "memorise". I wonder if it is so impressive as claim, why MOE did not train school teachers and we student will have an easier time. Imagine spending a week in their camp and being super achiever! Why need to memorise like crazy.

However my parents feel it might not work and further more it is pretty expensive.
To those who have been to the camp, care to share a little about this technique?

Hi

I have a physics question which i do not understand. If you know, please help.
three conducting balls, X, Y and Z are suspended vertically, side by side, without touching each other, by light insulating threads. X is charged positively. Y is negatively charged. Z is positively charged.
The following procedures are carried out:
1> Z is earthed and the earthing connection is then removed.
2> Y&Z are brought into contact and then separated
3> X&Y are brought into contact and then separated.
What is the resulting charges on Y & Z?

pls help me with this problem

Q>> Using the identities cos (2x) = 2 cos^2 (x) - 1 and a cos (x) + b sin (x) = (a^2 + b^2)^0.5 cos ( x - y ), where (y) is a constant, or otherwise, find the maximum and mimimum values of
11 cos^2 (x) + 3 sin^2 (x) + 6 sin(x)cos(x) + 5

Hence or otherwise solve the equation
11 cos^2 (x) + 3 sin^2 (x) + 6 sin(x)cos(x) + 5 = 15 for 0 deg <= (x) >= 360 deg

thank you
Cheers

Seeking help on a physics question.

three conducting balls, X, Y and Z are suspended vertically, side by side, without touching each other, by light insulating threads. X is charged positively. Y is negatively charged. Z is positively charged.
The following procedures are carried out:
1> Z is earthed and the earthing connection is then removed.
2> Y&Z are brought into contact and then separated
3> X&Y are brought into contact and then separated.
What is the resulting charges on Y & Z?

p/s >> i do not know how to create a new topic – Physics . can someone tell me how to do it.
Also how to remove/delete a post??

so do not need to buy culottes, is it possible