6. Solve ((xy) + xy(xy) + ye^x) dx + (x^2(xy) + e^x) dy = 0 . (10%)

2. A pressurized cylindrical tank with flat ends is loaded by torques T and tensile forces P as shown in Fig. 2. The tank has inner radius of r = 125 mm and wall thickness t = 6.5 mm. The internal pressure p = 7.25 MPa and the torque T = 850 N-m. What is the maximum permissible value of the forces P if the allowable tensile stress in the wall of the cylinder is 80 MPa? (20%)Fig. 2