Search found 176 matches

Sat Jan 25, 2014 9:12 pm
Forum: Secondary Level
Topic: Greece NMO 2013#P4
Replies: 2
Views: 2673

Re: Greece NMO 2013#P4

$\Delta ABC$ is inscribed in $c$ =>$c$ is the circumcircle of $\Delta ABC$ =>$c$ crosses the points $A,B,C$. Again,the circumcircles $c_1,c_2,c_3$ intersect $\Delta BOD$,$\Delta COD$,$\Delta AEZ$ in B,C and A [Circumcircles intersect the points of the triangle] But c crosses the points too.So they ...
Tue Jan 21, 2014 11:20 pm
Forum: Algebra
Topic: Trouble in Trigonometry
Replies: 3
Views: 1796

$sin5x$ $= sin5x + sinx - sinx$ $= 2 sin3x cos2x - sinx$ $= 2 (3sinx - 4sin^3 x) (1 - 2sin^2 x) - sinx$ $= 2 (8sin^5 x - 10sin^3 x + 3sinx) - sinx$ $= 16sin^5 x - 20sin^3 x + 5sinx$ Putting x=6, we get: $sin30= 16sin^5 6 - 20sin^3 6 + 5sin6$ Solving the equation, we get, $sin6=.105...$,so $cos6=\sqr... Sun Jan 19, 2014 11:42 am Forum: Divisional Math Olympiad Topic: Chittagong Junior 2013 / 9 Replies: 1 Views: 1379 Re: Chittagong Junior 2013 / 9 O,F যোগ করি। OF=ব্যাসার্ধ=OA=10। এখন,$OE^2+OG^2=OF^2=10^2=100.......(1)2(OE+OG)=24$বা$OE+OG=12$বা$OE=12-OG..............(2)$(1)নং এ বসিয়ে পাই,$(12-OG)^2+OG^2=100=> 2OG^2-24OG+144=100=> OG^2-12OG+22=0=> OG=6-\sqrt{14}$অর্থাৎ,$OE=6+\sqrt{14}OG=12-OE=6-\sqrt{14}$কিন্তু বৃত্তকলা$(AOB)=\fr...
Sat Jan 18, 2014 10:00 pm
Forum: Secondary Level
Topic: A Problem !!
Replies: 5
Views: 2489

Re: A Problem !!

3
2,2,11
3,5,7
5,5,5
Fri Jan 17, 2014 9:15 pm
Forum: Junior Level