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【332306】2.2 30°,45°,60°角的三角比 分层练习2

时间:2025-01-21 12:36:25 作者: 字数:2127字
简介:

30°45°60°角的三角比

基础训练

1.计算:

1sin60°+cos60°=_______;(2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> =_______

2.在Rt△ABC中,∠C=90°,∠A=30°BC=2,则斜边上的中线长为______

3.在△ABC中,∠A:∠B:∠C=123,则abc=_______

4.化简:(1)│tan60°2│=_______;2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> =______

5sin60°=cos_____=______cos60°=sin________=________

6.在Rt△ABC中,∠C=90°

1)若sinA= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> ,则∠A=______tanA=______

2)若tanA= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> ,则∠A=_______cosA=_________

7.计算:cos245°+tan60°·cos30°等于( )

A1 B <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> C2 D <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

8.在△ABC中,若∠A,∠B满足│sinA <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>+cosB <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>2=0,则△ABC是( )

A.等腰非等边三角形 B.等边三角形

C.直角三角形 D.钝角三角形



提高训练

9.求下列各式的值:

12sin30°3cos60°+tan45°; (2cos270°+cos45°·sin45°+sin270°




33tan30°2tan45°+2cos30°; (42cos30°+5tan60°2sin30°





 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>





10.已知2+ <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> 是方程x25xsinα+1=0的一个根,α为锐角,求tanα的值.





11.如图,在四边形ABCD中,∠A=60°,∠B=∠D=90°BC=2CD=3,求AB的值.

 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>



12.如图,∠C=90°,∠DBC=30°AB=BD,根据此图求tan15°的值.

 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>


拓展训练

13.已知tan2α-(1+ <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> tanα+ <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> =0,求锐角α的度数.







14.如图,已知锐角△ABC中,∠A,∠B,∠C的对边分别是abc

1)试说明:S△ABC= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> absinC

2)若a=30cmb=36cm,∠C=30°,求△ABC的面积.

 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>









参考答案

1.(1 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>21 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

22

31 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>2

4.(12 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

530° <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>30° <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

6.(160° <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>230° <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

7C 8B

9.(1 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>32 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> 2 46 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> 1 51+2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> 62

10 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

11 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a> 

122 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/920/" title="三角" class="c1" target="_blank">三角</a>

1345°60°

14.(1)略 (2270cm2