Math Homework Help - Tagged with sin

Prove that: `2cos(pi/13)cos({9pi}/13)+cos({3pi}/13)+cos({5pi}/13)=0` 

Posted by besterlinks October 21, 2012 at 1:30 PM via web. 1 educator answer. »

Show that y=xsinx is a solution of the equation y + y^"-2cosx = 0

Posted by cherrykisses October 16, 2012 at 3:36 PM via web. 1 educator answer. »

for every x from N* what is the limit of  (sqrt((sin(2nx)/(1+cos(nx))))/(4*(n^2)*(x^2)-(p^2))when x approach to (p/(2n))note that p = 22/7.

Posted by pourjour October 1, 2012 at 7:49 PM via web. Be the first to answer. »

Prove that  `sin x*cos(90-x)+cos^2(180-x)=1`  if x is an acute angle's measure.

Posted by zimzum95 September 10, 2012 at 7:34 PM via web. 1 educator answer. »

Prove that cos^6A+sin^6A = 1/4 (1 + 3cos^2A)

Posted by spsaroj June 26, 2012 at 10:42 AM via web. 1 educator answer. »

Simplify `(2sin2A-sin4A)/(2sin2A+sin4A)`  Please explain it. Thanks!

Posted by ume2 June 15, 2012 at 2:03 PM via web. 1 educator answer. »

Simplify sin^2(x-30)+sin^2(x+30)-sin^2x

Posted by baliksasa June 15, 2012 at 12:25 PM via web. 1 educator answer. »

Prove: sin A + sin B + sin C - 2sinA/2.sinB/2 = 2 sinC/2 so C= 120o  and cos A/2 cos B/2 cos C/2 - sin A/2 sin B/2 sin C/2 = 1/2 so ABC is a...

Posted by xiahsumy June 5, 2012 at 3:11 PM via web. 1 educator answer. »

prove the identity sin (angle)^2/ 1-cos(angle) =sec(angle)+1/sec(angle) 

Posted by ssdixon May 8, 2012 at 3:59 AM via web. 2 educator answers. »

prove the following identity algebraically: cos(angle)(sec(angle)-csc(angle))=1-cot(angle) 

Posted by ssdixon May 8, 2012 at 3:55 AM via web. 1 educator answer. »