cho goc bet xoy ve tia oy sao cho xy = 5/4 yoz
a, tinh xoy va yoz
b ke tia ot sao cho toy = 80 do tia oy co la tia phan giac cua toz ko vi sao
c , qua o ke them 20 duong thang nua sao cho cac duong thang nay deu ko chua cac tia ox,oy,oz ve duong tron tam o ban kinh r goi a la tap hop cac giao diem cua duong tron noi tren voi cac goc co o trong hinh ve .tinh so tam giac ma cac dinh cua no deu thuoc tap hop a
cho duong tron (O;R) va duong thang d co dinh khong cat duong tron.tu mot diem A bai ki tren duong thang d ke tiep tuyen AB voi duong tron (B la tiep diem ).tu B ke duong thang vuong goc voi Ao tai H tren tia doi cua tia BH lay C sao cho HC=HB.
a,chung minh C thuoc duong tron (O;R) va AC la tiep tuyen cua (O;R).
b,tu Oke duong thang vuong goc voi duong thang d tai i,OI cat BC tai K.chung minh OH.OA=OI.OK=R^2
Mình cần gấp giúp với!
bai 1:Cho duong tron tam O, day AB. cac tiep tuyen ke tu A,B cat nhau tai C. ke day CD cua duong tron co duong kinh OC(D khac A,B). CD cat cung nho AB cua (O) tai E (E nam giua C va D).Chung minh:
a/goc BED= goc DAE
b/DE^2=DA*BD
bai 2:Cho tam giac ABC deu noi tiep duong tron tam O. M la diem nam tren cung nho AB. chung minh:
a/MB+MA=MA
b/ke MH vuong goc voi BC, MI vuong goc voi AB, MK vuong goc voi AC. chung minh 3 diem H,I,K thang hang
bai 1 : s cua hinh tron co duong kinh 4,8dm
bai 2: s cua 1 hinh tron la 153,86cm2 , tinh chu vi hinh tron do
1/ đường kính 4,8dm => bán kính 2,4dm
Diện tích hình tròn là: r^2 x 3,14 = 2,4^2 x 3,14 = 18,0864( dm2)
2/ Ta có 153,86 = r^2 x 3,14 => r = 7 => đường kính 14cm
Chu vi hình tròn la: d x 3,14 = 14 x 3,14 = 43,96 cm
san tap the duc cua nha truong gom hinh chu nhat ABCD va 2 nua hinh tron co duong kinh AD va BC . Tinh dien tich san tap the duc
chieu dai HCN : 30m
chieu rong HCN: 20m vi vay nen duong kinh 2 nua hinh tron = 20m
cho goc bet xoy ve tia oy sao cho xoy = 5/4 yoz
a, tinh xoy va yoz
b, ke tia ot sao cho toy = 80 do tia oy co la tia phan giac cua toz ko? vi sao ?
c , qua o ke them 20 guong thang nua sao cho cac duong thang nay deu ko chua cac tia ox,oy,oz ve duong tron tam o ban kinh r goi a la tap hop cac giao diem cua duong tron noi tren voi cac goc o co trong hinh ve tinh so tam giac ma cac dinh cua no deu thuoc tap hop a
cho goc bet xoy ve tia oy sao cho xy = 5/4 yoz
a, tinh xoy va yoz
b ke tia ot sao cho toy = 80 do tia oy co la tia phan giac cua toz ko vi sao
c , qua o ke them 20 guong thang nua sao cho cac duong thang nay deu ko chua cac tia ox,oy,oz ve duong tron tam o ban kinh r goi a la tap hop cac giao diem cua duong tron noi tren voi cac goc o co trong hinh ve tinh so tam giac ma cac dinh cua no deu thuoc tap hop a
mai nop roi
mong giai gium
giot toan
Cho bieu thuc: P= \(\left(\dfrac{2\sqrt{x}}{\sqrt{x}+3}+\dfrac{\sqrt{x}}{\sqrt{x}-3}+\dfrac{3x-15}{9-x}\right):\dfrac{3}{\sqrt{x}+3}\)
a) Rut gon
b) Tinh gia tri cua P khi x=\(11-6\sqrt{2}\)
c) Voi x<9, tim gia tri lon nhat cua P
Bai 2: Cho nua duong tron tam O, duong kinh AB=2R. Tren cung nua mat phang bo AB dung 2 tiep tuyen Ax va By voi nua duong tron. Lay diem C thuoc nua duong tron, tiep tuyen tai C voi duong tron(O) cat Ax, By lan luot o M va N. Chung minh:
a) A,M,C,O cung thuoc mot duong tron O
b) Gia su AC cat By tai D. Chung minh: AC.AD=\(4R^2\)
c) AB la tiep tuyen cua duong tron duong kinh MN
d) Tim vi tri cua C tren duong tron de tong AM+BN co gia tri nho nhat
CAC BAN GIUM MINH VOI!! MINH DANG CAN GAP TRONG NGAY MAI NHE!! CAM ON CAC BAN NHIEU
Câu 1:
a: \(P=\dfrac{2x-6\sqrt{x}+x+3\sqrt{x}-3x+15}{x-9}\cdot\dfrac{\sqrt{x}+3}{3}\)
\(=\dfrac{-3\sqrt{x}+15}{\sqrt{x}-3}\cdot\dfrac{1}{3}=\dfrac{-\sqrt{x}+5}{\sqrt{x}-3}\)
b: Thay \(x=11-6\sqrt{2}\) vào P, ta được:
\(P=\dfrac{-\left(3-\sqrt{2}\right)+5}{3-\sqrt{2}-3}=\dfrac{-3+\sqrt{2}+5}{-\sqrt{2}}\)
\(=\dfrac{2-\sqrt{2}}{-\sqrt{2}}=-\sqrt{2}+1\)
bài 1:ve(A;cm),veM thuoc (A;3cm),ve N khong thuoc (A;3cm) so sanh AN va AM
bai 2:ve(O;3cm)ve OA=5cm cat duong tron tam O tai B ve(B;2cm)
a)cho biet vi tri diem O,diem A doi voi(B;2cm)
b)duong tron(B;2cm)cat OB tai M. chung to M la trung diem cua OB
