Đáp án:
Giải thích các bước giải:
Lời giải:
Ta biết:
sin2a+cos2a=1
⇒cos2a=1−sin2a=1−(23)2=59
⇒cosa=√53⇒cosa=53
tana=sinacosa=23:√53=2√5
cota=1tana=√52
Choose the best answer.
I think you should buy _____ pack of mineral water instead. And you can also buy _____ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______ cookies and soft candies.
We should decorate our living room with _____ orange banner. We also need ________ ribbons, balloons, party hats and costume.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.