2 when pcmq is rectangular, cq/cp=5/4. If the time is t, then t/(8-2t)=5/4 t=20/7s.
3 pcmq is a trapezoid (rectangle is a special trapezoid) with an area of (cp+mq)*cm/2 mq=4/5cq cm=3/5cq.
Let t be the moment, and the maximum trapezoidal area formula (upper bottom+lower bottom) * height /2.
That is, find the maximum value of (8-2t+4t/5)*3t/(5*2).
(24t-3.6t 2)/ 10 =- / 10
When the bracket is 0, the quadrilateral area is the largest, which is 40/ 10=4.
¢Ù Main courses of architecture major
Main subject: architecture
Main courses: architectural design foundation, architectural design and principle, Chinese and foreign ar