【導(dǎo)讀】⒌設(shè)AB,均為n階方陣，k?1，則下列等式正確的是．。A.若A是正交矩陣，則A?有意義，則C為5×4矩陣．。,，求滿足方程32AXB??

　　

【正文】 nt Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence. The balloon will slowly drift to the edge of space at 120,000 feet ( 專業(yè)好文檔 16 Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform. Below, the Earth bees the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he39。ll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jump When he jumps, he is expected to reach the speed of sound 690 mph (1,110 kph) in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him pletely. If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it39。s not needed. Instead, he plans to deploy his 270squarefoot (25squaremeter) main chute at an altitude of around 5,000 feet (1,524 meters). In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds. Even if everything goes as planned, it won39。t. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters). cause there 專業(yè)好文檔 17 Winger TuivasaSheck, who scored two tries in the Kiwis39。 2018 semifinal win over England, has been passed fit after a lowerleg injury, while Slater has been named at fullback but is still recovering from a knee injury aggravated against USA. Both sides boast 100% records heading into the encounter but Australia have not conceded a try since Josh Charnley39。s effort in their first pool match against England on the opening day. Aussie winger Jarryd Hayne is the petition39。s top try scorer with nine, closely followed by TuivasaSheck with eight. But it is recently named Rugby League International Federation player of the year Sonny Bill Williams who has attracted the most interest in the tournament so far. The Kiwi with a tournament high 17 offloads has the chance of being the first player to win the World Cup in both rugby league and rugby union after triumphing with the All Blacks in 2020. I39。d give every award back in a heartbeat just to get across the line this weekend, said Williams. The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。s antiracism taskforce, is in London for the Football Association39。s 150th anniversary celebrations and will attend City39。s Premier League match at Chelsea on Sunday. I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport. For me it39。s about how he felt and I would like to speak to him first to find out what his experienc e was. Uefa has opened disciplinary proceedings against CSKA for the racist behaviour of their fans during City39。s 21 win. Michel Platini, president of European football39。s governing body, has also ordered an immediate investigation into the referee39。s a ctions. CSKA said they were surprised and disappointed by Toure39。s plaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Baumgartner the disappointing news: Mission aborted. The supersonic descent could happen as early as Sunda. The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our daytoday weather lives. It will climb higher than the tip of Mount Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and into the stratosphere. As he crosses the boundary l ayer (called the tropopause),e can expect a lot of turbulence. The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform. They blew it in 2020 when they got caught cold in the final and they will not make the same mistake against the Kiwis in Manchester. Five years ago they cruised through to the final and so far history has repeated itself here the last try they conceded was scored by England39。s Josh Charnley in the opening game of the to urnament. That could be classed as a weakness, a team undercooked but I have been impressed by the Kangaroos39。 focus in their games since then. They have been concentrating on the sort of stuff that wins you tough, even contests strong defence, especially on their own goalline, pleting sets and a good kickchase. They39。ve been great at all the unglamorous stuff that often goes unnoticed in the stands but not by your teammates. It is as though their entire tournament has been preparation for the final. In Johnathan Thurston, Cooper Cronk, Cameron Smith and either Billy Slater or Greg Inglis at full back they have a spine that is unmatched in rugby league. They have played in so many high pressure games a priceless asset going into Saturday. The Kiwis are a lot less experienced but winning a dramatic match like their semi final against England will do wonders for their confidence. 專業(yè)好文檔 18 They defeated Australia in the Four Nations final in 2020 and the last World Cup, and know they can rise to the big occasion.