如图,三角ABC中,角B=角C,AB=AC=12cm,BC=8cm,点D是线段AB的中点,点P和Q是线段BC和AC上的动点,点P以每秒
如图,三角ABC中,角B=角C,AB=AC=12cm,BC=8cm,点D是线段AB的中点,点P和Q是线段BC和AC上的动点,点P以每秒2cm的速度从点B出发,沿线段BC的...
如图,三角ABC中,角B=角C,AB=AC=12cm,BC=8cm,点D是线段AB的中点,点P和Q是线段BC和AC上的动点,点P以每秒2cm的速度从点B出发,沿线段BC的方向运动;同时点Q从点C出发,沿线段CA的方向运动,已知AB=AC,角B=角C,求:若点Q的运动速度与点P的运动速度相等,当运动时间t=1秒时,试比较线段DP与PQ的大小关系并说明理由?
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解:
(1)当t=1时,BP=2cm CP=6cm CQ=2cm,因为D是AB中点所以BD=AD=6cm,因为∠B=∠C,BP= CQ=2cm ,BD=CP=6cm。所以△DBP全等于△PCQ(SAS),所以DP=PQ
(2)设点Q速度为x,则t秒后CQ长度为x cm,因为P的速度为2cm每秒,所以t秒后BP长度为2t cm CP=8-2t(cm)。当DB=CP,∠B=∠C,BP=CQ时,△DBP全等于△PCQ(SAS),列方程解得t=1,x=2。当DP=CQ,∠B=∠C,BP=CP时,,△DBP全等于△QCP(SAS),列方程解得t=2秒,x=3cm。
(1)当t=1时,BP=2cm CP=6cm CQ=2cm,因为D是AB中点所以BD=AD=6cm,因为∠B=∠C,BP= CQ=2cm ,BD=CP=6cm。所以△DBP全等于△PCQ(SAS),所以DP=PQ
(2)设点Q速度为x,则t秒后CQ长度为x cm,因为P的速度为2cm每秒,所以t秒后BP长度为2t cm CP=8-2t(cm)。当DB=CP,∠B=∠C,BP=CQ时,△DBP全等于△PCQ(SAS),列方程解得t=1,x=2。当DP=CQ,∠B=∠C,BP=CP时,,△DBP全等于△QCP(SAS),列方程解得t=2秒,x=3cm。
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Beijing 9 (Copenhagen, 9 nearby time) messages, the entire prize cash amounted to $ 220,000 from the WTA Tour Saidan Mai International Open to continue your struggle round 2, the world number 86 contrary to the Chinese player Zhang Shuai Kazakhstan Worth Copperfield Isinbayeva, the results of Zhang Shuai worked tough to 6-3/2-6/6-3 out 3 opponents last eight.
These days will be the world's Zhang Shuai, ranked No. 86 ranking using the world's Worth 211 career first met Copperfield Isinbayeva,wholesale watches, who swept 2-0 in the initial round from the Australian champion Dokic. After the start of the race today, the very first 2 games of two people to break forward and backward, after the very first 5 games to Zhang Shuai 2-3 behind, but she was 7 and 9 with the Council Board to total two consecutive break, Paul successfully serve their particular hair,drop ship wholesalers, extending its love to recover 4 Council to win the first set 6-3. Second set, Dementieva took the lead Worth Copperfield complete break, after which once more at the 5th Board break, made a 4-1 lead. 1-5 big deficit seventh flowers and did not stop trying, she was tenacious, following saving a break point Paul made. Helpless or struggling to break in the eighth inning,wholesale, 2-6 lost the second set.
Wal-baby to a third set created from 3 break points 40-0, while Zhang Shuai struggling to save lots of the very first two, but still in the third opponent around the break. Thankfully, she rapidly finished the 2nd game back broken, the Council points for the 1-1. Paul made after both men came to the 3-3, Zhang Shuai break in the eighth inning to total victory ushered as part of his own serve game! She also did not encounter any danger ,wholesale Oakley,6-3, the conclusion with this time-consuming One hour 55 minute fight. They serve the whole game in every areas of the performance in general, Zhang Shuai saved 14 break points in 10 of her next opponent will be No. 4 seed in the baby and also the Netherlands, the Czech girl who Safa Nuo between Krajicek .
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