$y=\sin^4x+\cos^4x$
$=(\sin^2x)^2+(\cos^2x)^2$
$=[(\sin^2x)^2+2\sin^2x\cos^2x+(\cos^2x)^2]-2\sin^2x\cos^2x$
$=[(\sin^2x+\cos^2x)^2]-2\sin^2x\cos^2x$
$=1-2\sin^2x\cos^2x$
Áp dụng HĐT: $a^2+2ab+b^2=(a+b)^2$
Giải thích các bước giải:
$\begin{array}{l}y = {\sin ^4}x + {\cos ^4}x\\ = {\left( {{{\sin }^2}x} \right)^2} + {\left( {{{\cos }^2}x} \right)^2}\\ = {\left( {{{\sin }^2}x + {{\cos }^2}x} \right)^2} - 2{\sin ^2}x{\cos ^2}x\left( {HDT:{a^2} + {b^2} = {{\left( {a + b} \right)}^2} - 2ab} \right)\\ = 1 - 2{\sin ^2}x{\cos ^2}x\\ = 1 - 2{\left( {\sin x\cos x} \right)^2}\\ = 1 - 2{\left( {\dfrac{1}{2}\sin 2x} \right)^2}\\ = 1 - \dfrac{1}{2}{\sin ^2}2x\end{array}$
LÀM ĐẦY ĐỦ CHI TIẾT CHUYÊN GIA ANH GIÚP VS BN NÀO SPAM LÀM KO CHI TIẾT ĐẦY ĐỦ HAY CHÉP MẠNG NHỜ MOD XÓA GIÙM CẦN GẤP MK KÍM MẠNG RÒI KO CÓ ĐÂU! use one of the adjectives in the box to complete each sentences: ___________________________ frightening | boring | tiring surprising interesting satisfying frightend bored tired surprised interested | satisfied | ____________________________ 1) I find being alone at night in a strange place very.............. 2) Jack, don't sit around looking so ................. Go and do something! 3) My job is so ................ I work a lot at the office and then have to spend another hour or two doing paperwork at home. 4) the room was in darkness when I entered and then suddenly the lights came on and everyone was shouting "Happy birthday" . I was so ............. 5) if two big dogs attracked you, would you be really...............? 6) The most ............... thing about An is that she got promotion and didn't even tall anyone. 7) Look it's after midnight and I am feeling really.......................... .I'm sorry but I must go to bed. 8) My brother-in-law thinks he's a very .................. person but he bores me to tears! 9) I thinks chess is a ......................... game. I really don't understand what attracts people to it. 10) Are you ......... with your meal,sir? Perhaps I can bring you some more bread. 11) Jenny are you ......................... in what I'm saying or not? At least show some enthusiasm! 12) Being a nurse is a difficult job I'm sure it is very..........................................
Chuyển danh từ sau sang dạng số nhiều: radio
Giúp mình câu 6 với ạ, mình cảm ơn và sẽ tích ctlnn + đúng nhất
Năm bao nhiêu Bác Hồ ra đi tìm đường cứu nc ở tàu nào
Giúp em với em hok bt cách giải
93 tỷ viết bằng số..........................
• Use the correct form of the word given in each sentence. 1, Mouawad designers have drawn ___________ for this unique design from the principles of strength, women's empowerment, and communities that are associated with the Miss Universe organization. (INSPIRE) 2, Finger-rings and ear-studs, stone necklaces and ornamental chokers, brightly-hued bracelets, and ___________ shaped pendants are there in rich profusion. (INNOVATE) 3, The announcement comes as a result of a national survey, which revealed one in five new appointments for secondary school teachers to be ___________ . (SATISFY) 4, In 1995, the proposal and unique approach for the development of the major sites were created by a combination of Virginia ___________, historians, and tourism authorities. (PRESERVE) 5, Until previously, tales of persons declining Queen Elizabeth's accolades have been based only on leaked lists or information provided by the ___________ . (NOMINATE) 6, The weights of animal carcasses likewise show progress, with the increase in the size of lambs and calves the best indicators of ___________ improvements. (PRODUCE) 7, The French and the Spanish captured numerous West Indian islands ___________ and resembled to be on the approach of ousting the British entirely. (EFFECT) 8, In the case of subsidized schools, the main costs such as teachers' salaries and building maintenance are borne ___________ by the Flemish government. (COMPLETE) 9, European legislators are called upon, through ___________ pumped into the open ocean, to tackle the luxury liners threatening marine life. (POLLUTE) 10, Nevertheless, an attempt to reclaim Malta ended _____________ by supporting the Arabs and massacring the Byzantine garrison among local populations. (DISASTER)
bài 1: 10 - 2x = 25 - 3x bài 2: cho 4 số 2;3;4;6 dùng phép cộng, trừ viết ra 20 cặp phân số bằng nhau Ví dụ: 2/4 bằng 3/6 vì 2.6= 3.4
Hoà tân hoàn toàn 14g sắt vào dd axit Clohiđric (HCl) dư A . Viết pthh B. Tính KL muối tạo thành C. Tính thể tích khí hiđro sinh ra ở đktc
Bạn Khiêm có 25 viên bi .Bạn Thái có nhiều hơn bạn ....... Ở trên rồi
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