Recent content by delefemiaoa

I have used ur suggestion,as follows common ration = 3-1 e2Өni, first term = 1, however I got stucked.

Homework Statement Given that Wn = 3-n cos 2nӨ for n = 1, 2, 3, …, use de Moivre’s theorem to show that 1 + W1 + W2 + W3 + … + WN-1 = [ 9 – 3 cos2Ө+ 3-N+1 cos2(N-1)Ө - 3-N+2 cos2NӨ] / [10 – 6cos2Ө] Hence show that the infinite series 1 + W1 + W2 + W3 + … is convergent for all values...

Thanks a lot, I can now understand how to solve it.

I have done that before but I can not deduce any relation between x and y.

Homework Statement A log of wood which is approximately circular in cross section has diameter equal to 0.5m. Calculate the maximum area of the rectangular timber section that can be obtained from the log. Homework Equations The Attempt at a Solution No idea of solution