‌‌ Area ‌=(4‌cos‌θ+2sin‌θ)(2‌cos‌θ+4sin‌θ) ‌=8cos2θ+16sin‌θ‌cos‌θ+4sin‌θ‌cos‌θ+8sin‌2θ ‌=8+20sin‌θ‌cos‌θ ‌=8+10sin‌2θ ‌‌ Max Area ‌=8+10=18(sin‌2θ=1)θ=45∘ ‌(a+b)2=(4‌cos‌θ+2sin‌θ+2‌cos‌θ+4sin‌θ)2 ‌=(6‌cos‌θ+6sin‌θ)2 ‌=36(sin‌θ+cos‌θ)2 ‌=36(√2)2 ‌=72