【初中数学公式】, Bar 数学, Purasbar

There are currently 229 posts.

	Floor 201 啊啊是谁都对 6/30/13 17:38 tanA+tanB=sin(A+B)/cosAcosB
	Floor 202 啊啊是谁都对 6/30/13 17:38 tanA-tanB=sin(A-B)/cosAcosB
	Floor 203 啊啊是谁都对 6/30/13 17:39 ctgA+ctgBsin(A+B)/sinAsinB -ctgA+ctgBsin(A+B)/sinAsinB
	Floor 204 啊啊是谁都对 6/30/13 17:39 1+2+3+4+5+6+7+8+9+…+n=n(n+1)/2
	Floor 205 啊啊是谁都对 6/30/13 17:39 1+3+5+7+9+11+13+15+…+(2n-1)=n2
	Floor 206 啊啊是谁都对 6/30/13 17:39 2+4+6+8+10+12+14+…+(2n)=n(n+1)
	Floor 207 啊啊是谁都对 6/30/13 17:39 12+22+32+42+52+62+72+82+…+n2=n(n+1)(2n+1)/6
	Floor 208 啊啊是谁都对 6/30/13 17:40 13+23+33+43+53+63+…n3=n2(n+1)2/4
	Floor 209 啊啊是谁都对 6/30/13 17:40 12+23+34+45+56+67+…+n(n+1)=n(n+1)(n+2)/3
	Floor 210 啊啊是谁都对 6/30/13 17:40 正弦定理 a/sinA=b/sinB=c/sinC=2R 注：其中 R 表示三角形的外接圆半径