1. The problem statement, all variables and given/known data A heavy weight is suspended by a cable and pulled to one side by a force F. How much force is required to hold the weight in equilibrium at a given distance x to one side. From classical mechanics, TcosX= W and TsinX=F. Find F/W as a power series of X(angle). Often in a problem like this, what we know is not X, but x(displacement) and l(length of string). Find F/W as a series of powers in x/l 2. Relevant equations TcosX=W TsinX=F 3. The attempt at a solution How do I calculate the power series for tanX? I've searched online but the people at yahoo answers got it wrong http://en.wikipedia.org/wiki/Taylor_series Wikipedia gives the answer but no route to it. SinX= x/l cosX= ((l-x)(l+x))^0.5/l F/W = x/(l-x)(l+x)^0.5??????