c: \(=4\sqrt{5}+4\sqrt{3}-4\sqrt{3}-2\sqrt{5}=2\sqrt{5}\)
c: \(=4\sqrt{5}+4\sqrt{3}-4\sqrt{3}-2\sqrt{5}=2\sqrt{5}\)
Giups tui bai hinh voi a
Bai 1:
giai bai toan sau = cach lap phuong trinh hoac he phuong trinh
cau 1:
hai to cung lam chung 1 cong viec trong 12 gio xong .Nhung 2 to cung lam 4 gio thi to 1 di lam viec khac, to 2 lam not trong 10 gio thi xong . Hoi moi to lam rieng trong bao lau thi xong cong viec?
cau 2:
hai voi nc cung chay vao be ko chua nc trong 1 gio 30 phutthi day be . neu voi 1 chay trong 15 phut roi khoa lai sau do mo voi 2 chay trong 20 phut thi dc 20% be . Hoi moi voi chay rieng trong bao lau se day be?
cau 3:
luc 7 gio mot oto di tu A den B, sau do 30 phut mot xe may di tu B ve A voi van toc kem van toc oto la 24 km/h. Oto di den B dc 1 gio 20 phut thi xe may moi den A. tinh vsn toc moi xe . Biet quang duong tu AB la 120km
Tam giac mnp vuong tai M mq vuong goc np, qc vuong goc mn,qd vuong goc mp,mk trung tuyen , qn=9cm,qp=16cm.
a, mq =? ; MNP=?
b,MN.mc=mp.md
c, CHung minh QMN = goc KMP
lam cau C thui ko can lam cau A voi Cau B
Giai giup em bai nay voi a. : x(x+1)=y2+1
ai giup em giai bai toan nay voi : Cmr 2a^2+b^2+c^2>=*a*(b+c)
Hinh hoc 9: Em co 2 bai toan hinh hoc lop 9 de chuan bi cho thi HKI, cac anh chi vui long giai giup em cau d voi. Cau a, b, c thi em lam duoc roi.
Bai 1:
Cho (O,R) duong kinh BC . Goi A la 1 diem tren (O) sao cho AC< AB
a) Cm: tg ABC vuong va giai voi AC=R
b) Goi H la trung diem AB . Tia OH cat tiep tuyen tai B cua (O) tai D. Cm: DA la tiep tuyen cua (O) va 4 diem D, B, O, A thuoc duong tron.
c) Tia DO cat (O) tai I va K (I nam giua D va O). Cm: DA.DA = DI.DK
d) Goi E, F lan luot la trung diem cua DA, DB, tren EF lay diem M bat ky, ve tiep tuyen MT voi (O). Cm: MT = MD
Bai 2:
Cho tam giac ABC vuong tai A co duong cao AH. Ve duong tron tam A, ban kinh AH. Tu H ve day HE vuong goc voi AC tai S (S thuoc AC). Tu B ve tiep tuyen BD cua duong tron tam A (D khac H).
a) Cm: CE la tiep tuyen cua duong tron tam A
b) Cm : BD + CE = BC
c) Duong thang DC cat (A) tai V(V khac D). Cm D, A, E thang hang va CS.CA = CV.CD
d) Duong tron tam O duong kinh BC cat duong tron tam A tai M va N. Goi I la trung diem cua AH. Cm: OA vuong goc MN va ba diem M, I, N thang hang.
Ai hoc lop 5 thi moi tra loi duoc cau nay : Do la bai Tieng Viet Tap 2 bai : Cong viec dau tien .
Cau 1 : Cau nao duoi day la cau ghep ?
a) Mot hom , anh Ba Chan goi toi vao trong buong dung noi anh giao viec cho toi ngay truoc .
b) Nhan cong viec toi vinh du dau tien nay , toi thay long cu bon chon , thap thom .
c) Toi rao buoc va truyen don dan dan roi xuong dat .
d) May ten linh ma ta hot hai xach sung chay ram ram .
Cau 2 :Tu " Viec " trong cau : " Em chi muon lam that cho Cach Mang " la :
a) Dong tu
b) Tinh tu
c) Dai tu
d) danh tu
Cau 3 : Dong vai chi Ut ke khoang 3 - 5 cau ve tam trang khi di rai chuyen
Mn giup em cau nay a!
giups mk voi