0" data-width="433" data-height="50" class="exam-img-50 exam-img" data-size="5164" data-format="png" style="max-width:100%">故单增,f\left(0\right)=0" data-width="151" data-height="26" class="exam-img-26 exam-img" data-size="2375" data-format="png" style="max-width:...
由题可知,所给的已知条件为向量,以及题目所求为" data-width="76" data-height="29" class="exam-img-29 exam-img" data-size="923" data-format="png" style="max-width:100%">,由此可知本题需要利用向量的夹角余弦值公式的基本性质和运算法则进行分析计算。 向量的夹角余弦值公式为\ =\frac{\ov...
解:已知1" data-width="55" data-height="19" class="exam-img-19 exam-img" data-size="669" data-format="png" style>,0" data-width="49" data-height="19" class="exam-img-19 exam-img" data-size="674" data-format="png" style>,, 可知:,0" data-width="90" data-height="20...
1" data-width="100" data-height="46" class="exam-img-46 exam-img" data-size="1660" data-format="png" style>,即得,0" data-width="135" data-height="46" class="exam-img-46 exam-img" data-size="1934" data-format="png" style>,即0" data-width="106" data-height="46" class...
所以\frac{9}{2}" data-width="85" data-height="38" class="exam-img-38 exam-img" data-size="1424" data-format="png" style="max-width:100%">. (2)因为,则, 已知0" data-width="37" data-height="15" class="exam-img-15 exam-img" data-size="595" data-format="png" style="ma...
由题意,得,0" data-width="49" data-height="20" class="exam-img-20 exam-img" data-size="779" data-format="png" style="max-width:100%">,0" data-width="47" data-height="20" class="exam-img-20 exam-img" data-size="807" data-format="png" style="max-width:100%">,所以,当...
当1" data-width="47" data-height="19" class="exam-img-19 exam-img" data-size="592" data-format="png" style="max-width:100%">时,令,得到 当时,0" data-width="85" data-height="26" class="exam-img-26 exam-img" data-size="1265" data-format="png" style="max-width:100%"...
由向量内积公式可知,若向量,,则向量内积=x_1x_2+y_1y_2" data-width="204" data-height="23" class="exam-img-23 exam-img" data-size="2657" data-format="png" style="max-width:100%">.由题意,已知已知向量,,利用向量内积公式,则=0\cdot1+2\cdot\left(-1\right)=-2" data-width="28...
解:已知函数I/0,可知函数过定点I/0,所以PD=12的坐标为I/0,由此可得:I/0.对于A,因为I/00" data-width="45" data-height="15" data-size="677" data-format="png" style="max-width:100%">,I/00" data-width="40" data-height="15" data-size="592" data-format="png" style="max-width...
已知实数α0,y0,x+y=3/40,y>0,x+y=\frac{3}{4}" data-width="203" data-height="45" data-size="2995" data-format="png" style="max-width:100%">所以 1/x+1/y=4/3(x+y)(1/x+1/y)=4/3(2+y/x+x/y)≥4/3(2+2√(y/x⋅x/y)=(16)/3当且仅当α=y=3/8时取等号。