Let ABC be a triangle with A(3,0,0),B(0,6,0),C(0,0,4) and let H(x,y,z) be its orthocenter .Find the coordinates of point H ?

solve 30a+75b+110c+85d+255e+160f+15g+12h+120i=8000 over the positive integers

solve 30a+75b+110c+85d+255e+160f+15g+12h+120i=800000 over the positive integers

  Solving trigonometry Equations  sin^2(2x)-cos^2(8x)=0.5cos(10x)

Sum(a^(k/a^k), k= 1..n);