matlab用stem画出𝑥(𝑛) = (0.6)^𝑛𝑢(𝑛)卷积h(𝑛) = (−0.9)^𝑛𝑢(𝑛)的图像，将n在[0,70]和[1,35]的卷积图像用不同的颜色画在同一张图像里

n = 0:70;
x = (0.6).^n.*(n>=0);
h = (-0.9).^n.*(n>=0);
y = conv(x,h);

figure;
stem(n,y(1:length(n)),'r'); % 绘制n在[0,70]的卷积图像，红色
hold on;
stem(n,y(2:length(n)+1),'b'); % 绘制n在[1,35]的卷积图像，蓝色
xlabel('n');
ylabel('y(n)');
title('Convolution of x(n) and h(n)');
legend('n=[0,70]','n=[1,35]');