4" x 4" x 12" (inches)是什么意思

matlab 画图求助公式为w= ((P*r_d^4)/64*K)*(1-(r/r_d )^2 )^2+c K= E*t^3/(12-12*nu^2) P = 15psi, rd = 15 inches, E = 18 x 106 psi, t = 0.08 inche nu=0.3 . Draw a surface plot of the membrane. Nameyour function ‘SurfPlotQ1.m’:a.制造一 x*x*x-4x*x+12x分解因式 3x·x-5x-122x·x·x-x·x-4x+3x·x·x-6x-5x·x+6x+64x·x+12x+7 通分:x+4/x^2-8x+15,x-5/x^2+x-12,x-3/x^2-x-20 x(x+4)=8x+12 x(x+4)=8x+12 x*9+x*36+4x*12 5 feet and 6 inche是多高? *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || (x^+4x)^+7(x^+4x)+12 x^2(x-1)^2-4x(x-1)-12 x平方-x-12/x平方-x=4 4x+2x+x-3x=12 x^2-6x+5/-x^2+4x+12 分式因式分解：4x(x-2) / 12x（x+2) x平方-x-x平方-x分之12=4 3x-{-4x+{5x-(12x-10]+2} (x-2)/(x+2)-(x^2+12)/(x^2-4)