2(xy+1/3x^3-y+pi^4) 多项式求它是几次几项式

2(xy+1/3x^3-y+pi^4) 多项式求它是几次几项式 matlab的solve用法定义syms x y a1 a2equ1=1/120 - ((2*a2)/81 + (pi*a1)/12 + pi^2*(a2/405 + 1/12) + (pi^3*a1)/120)/pi^4equ2=-(a2/128 + (2*pi*a1)/81 + pi^2*(a2/960 + 2/81) + (pi^3*a1)/405 - pi^4/405)/pi^5输入solve('方程1', '方程2', 'a1', 'a1') 用matlab求二重积分[1+cos(6*pi*x+8*pi*y)]*exp(-j*2*pi*(3*x+4*y)),试了好多次貌似都有错syms x y>> double (int(int(1+cos(6*pi*x+8*pi*y)*exp(-j*2*pi*(3*x+4*y)),-inf,inf),-inf,inf))Warning:Could not attach the property of being closeto the 求大神解答一下我这MATLAB程序哪里有问题x=[0:0.01:1]b=[(2*pi)/45,pi/18,pi/12,pi/6,pi/3,pi/2,(2*pi)/3]a=1./(.4*tan(b./2))y=a.*x.^2plot(x,y) MATLAB 下面这个代码错在哪里,还有就是什么时候定义函数加‘’syms x;x=-pi:0.01:pi;y=cos(tan(pi*x));subplot(2,2,1);plot(x,y)axis([-pi,-pi/2])subplot(2,2,2);plot(x,y)axis([-pi/2,0])subplot(2,2,3);plot(x,y)axis([0,pi/2])subplot(2,2 XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 三角函数关于直线对称问题?已知定义在区间[-3pi/2,pi]上的函数y=f(x)的图像关于直线x=-pi/4对称,当x在[-pi/4,pi]上时,f(x)=2sin(2x/3+pi/3).求x在[-3pi/2,-pi/4]上时,f(x)的表达式是什么? 为什么y=2sin(3x-3/4 *pi) 可以写成y=-cos(3x+3/4 *pi) 化简sin(2x-pi)sin[x+(3/2)pi]/cos[x+(5/2)pi][1-sin(pi+x)] 怎么用matlab解方程组 a+b=(pi)/2,a*x+b*y=(pi)^2/8,a*x^2+b*y^2=(pi)^3/24,a*x^3+b*y^3=(pi)^4/64 matlab中画三维离散点,参数s是关于点的变量,想利用colorbar实现每个点的颜色对应a的值,即4维图x=[];y=[];z=[];s=[];for a1=2/3*pi:pi/20:17/12*pi;for a2=-7/6*pi:pi/20:-1/2*pi;for a3=-1/6*pi:pi/20:2/3*pi;b1=cos(a1)*cos(a2)*cos 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 已知y=sinx/(1+cosx),x属于(0,pi),当y'=2时,x等于（ ）A.pi/3B.2/3piC.pi/4Dpi/6你的答案是正确的.