已知圆的极坐标方程为p^2-4√2pcos(θ-π/4)+6=0,
问题描述：
已知圆的极坐标方程为p^2-4√2pcos(θ-π/4)+6=0,
（1）将极坐标方程化为直角坐标方程
（2）设点p(x,y)在该圆上,求x+y的最值.
答
(1) p² - 4√2pcos(θ-π/4) + 6 = 0p² - 4√2p [cosθcos(π/4) + sinθsin(π/4)] + 6 = 0 (利用两角差的馀弦公式)p² - 4√2p [cosθ (1/√2) + sinθ (1/√2)] + 6 = 0p² - 4pcosθ - 4psin...