化简sin^2(a+35°)+tan(315°-b)*cot(b+45°)+cos^2(145°-a)

化简sin^2(a+35°)+tan(315°-b)*cot(b+45°)+cos^2(145°-a)

原式=sin²(a+35)+[-cos(180-(145-a))]²+tan(315-b-360)cot(b+45)
=sin²(a+35)+[-cos(a+35)]²+tan(-45-b)cot(b+45)
=sin²(a+35)+cos²(a+35)-tan(b+45)cot(b+45)
=1-1
=0

是第二种
第一种
=(a^4-a²)+4(a-1)
=a²(a+1)(a-1)+4(a-1)
=(a-1)(a³+a²+4)
=(a-1)(a³+2a²-a²+4)
=(a-1)[a²(a+2)-(a+2)(a-2)]
=(a-1)(a+2)(a²-a+2)