# Recently Active Trignometry Questions

• If \sqrt {a+b} \tan \frac {\theta}{2}=\sqrt {a-b} \tan \frac {\phi}{2} then prove that (b-a\ sec \theta)(b+a\cos \phi)\leq 0 ...
replied2009-11-09 06:25:26
• in a triangle,R=2r then the triangle is a)right angle b)isosceles c)equilateral d)none ...
replied2009-11-09 01:15:06
• 2sin45/4Â°=âˆš2-âˆš2+âˆš2 prove this ? ( the first root is the main root.the second and the third root is under the main root). ...
replied2009-11-08 21:20:00
• Solve \left|\sin x\right|^{\sin ^2x-\sin x-2 }<1 ...
replied2009-11-07 05:10:33
• If a right angle is divided into three parts Î±,Î²,Î³ prove that for all possible divisons, tanÎ±+tanÎ²+tanÎ³>1+tanÎ±tanÎ²tanÎ³ ...
• if Î± lies in the fourth quadrant and cosÎ±=3/7 find the values of sinÎ±/2 and cosÎ±/2 ? ...
replied2009-11-07 01:30:39
• 1)Evaluate \sum_{0}^{infinity}{sin(n\alpha )/n} = ??? (n varies from 0 to infinity) [\alpha\varepsilon (0,2\pi )] 2)Find the sum of \sum_{r=00}^{infity}{\frac{sinr\alpha }{sin^{r}\alpha }} ...
replied2009-11-03 21:56:46
• if....\theta =\frac{2\pi }{2009}.... then.....cos\theta cos 2\theta cos 3\theta ..............cos 1004\theta ........is equal to ..... ...
replied2009-10-26 07:12:17
• if x,y,z are real numbers satisfying the relations $x+y+z = 1\quad\textrm{and}\quad\arctan x+\arctan y+\arctan z =\frac{\pi}{4},$ prove that $x^{2n+1}+y^{2n+1}+z^{2n+1}= 1$ holds true for all positive integers n . ...
replied2009-10-18 18:45:27
• 7)sin x<1/2 Â½=sin 30 =sin(180-30)=sin 150 or, sin30<1/2 and sin 150 >1/2(why? And how?) or, x belongs to (0,30) union (150,360) [given: 0<x<360] I want a complete explanation. 8) Give the general soln of x: lo ...
replied2009-10-16 01:32:08
• Reduce to simplest form tan^{-1}(\frac {xcos\theta}{1-xsin\theta})-cot^{-1}(\frac {cos\theta}{x-sin\theta}) ...
replied2009-10-06 12:26:19
• If x=cosec(tan-1(cos(cot-1(sec(sin-1a))))) and y=sec(cot-1(sin(tan-1(cosec(cos-1a))))) where 0â‰¤aâ‰¤1.Find relationship between x and y ...
replied2009-10-04 06:11:52
• Find the roots of x^2+(4x^3-3x)^2=1 ...
replied2009-10-01 05:58:02
• \\x_1-1/x_1=2x_2 \\x_2-1/x_2=2x_3 \\x_3-1/x_3=2x_4 \\x_4-1/x_4=2x_1 Solve this set of equations.. ...
replied2009-10-01 03:30:38
• Q1 If cos-1Î» +cos-1Î¼ +cos-1Î½=3Ï€ then prove that Î»Î¼+Î¼Î½+Î»Î½=3 Q2 If 2nÎ£i=1 sin-1xi=nÏ€ then prove that 2nÎ£i=1xi=2n ...
replied2009-09-30 05:25:59
• *Image* Q3 *Image* ...
replied2009-09-30 05:09:39
• If Î£sin-1x=Ï€,then prove that x4+y4+z4+4x2y2z2=2(x2y2+y2z2+z2x2) ...
replied2009-09-30 00:36:40
• Just saw this problem in some Coaching Institute material. If cos A + cos B + cos C = sin A + sin B + sin C = 0, prove that cos (A-B) + cos (B-C) + cos (C-A) = -3/2 ...
replied2009-09-28 00:12:08
• errr....just got confused...which one of these is correct?? sin(a) + sin(a+d) + sin(a+2d) + sin(a+3d) + ...... + sin(a+nd) = \frac{sin\left(\frac{2a+nd}{2}\right)sin\left(\frac{nd}{2} \right)}{sin\left(\frac{d}{2} \right)} OR ...
replied2009-09-26 02:12:21
• In a triangle ABC , find the least value of, cot A/2 * cot B/2 * cot C/2 * cos A/2 * cos B/2 * cos C/2 ...
replied2009-09-22 04:58:41
• show that the equation secÎ¸ + cosecÎ¸ = c has two solutions between 0 and 2Ï€ if c2 < 8 and four solutions if c2 > 8. I've tried but didn't get the correct answer. ...
replied2009-09-21 21:31:30
• Please explain this question, how the solution has been obtained? *Image* ...
replied2009-09-21 07:39:05
• 1) If sin x + sin y = 3(cos y - cos x), then find the value of sin3x + sin3y ? 2) If sin (x/2) + cos (x/2) = -1/2 , 3pie/2 < x < 2pie, then the value of sin2x? ...
replied2009-09-21 00:38:43
• (1) find value of x in cos7x+sin4x = 1 ...
replied2009-09-20 04:57:06
• solve cos2x-sinx=0 ...
replied2009-09-19 13:32:26
• evaluate: âˆž Î£n=1(sin(nÎ¸))/n ...
replied2009-09-19 04:07:53
• solve the following: tanx-sinx=\frac{x^{3}}{2} ...
replied2009-09-18 20:51:23
• find (p) so that the given equation has real solutions (cos p -1)x2 + (cos p)x + sin p =0 ...
replied2009-09-18 08:40:51
• 1+ \frac{cos\theta }{cos\theta } + \frac{cos2\theta }{cos^2\theta } + \frac{cos3\theta }{cos^3\theta } + ... upto \infty for those whose latex is not working 1+ cosÎ¸/cosÎ¸ + cos2Î¸/cos2Î¸ + cos3Î¸/cos3Î¸ + ... upto âˆž ...
replied2009-09-18 06:20:27
• Prove that tan-1( 1+x - 1-x )/( 1+x + 1-x ) = Ï€/4-1/2 Cos-1x 0<x<1. ...
replied2009-09-16 05:59:45