Sunday

February 1, 2015

February 1, 2015

Posted by **marley** on Monday, June 6, 2011 at 11:53pm.

Q1. If sinx +siny=3(cosy-cosx) then the value of sin3x/sin3y.

Q2. If sina ,cosa,and tan a are in g.p.then cos cubea+cos square a is equal to

- maths (trigonometry) -
**Anonymous**, Tuesday, June 7, 2011 at 1:43amQ1.

From the given relation, we can write, 3 cos x + sin x = 3 cos y - sin y

put r cos ƒ¿=3 and r sin ƒ¿ = 1 , then we get , r = ã 10, tanƒ¿= 1/3

so r cos ( x - ƒ¿) = r cos (x+ƒ¿)

x = - y or x = }(y+ƒ¿)

clearly x = - y satisfies the equation

therefore, x = - y

so 3x = -3y

sin 3x = sin (-3y) = - sin 3y

sin 3x / sin 3y = -1

- maths (trigonometry) -
**Anonymous**, Tuesday, June 7, 2011 at 1:44amƒ¿= Greek letter Alpha

- maths (trigonometry) -
**Mgraph**, Tuesday, June 7, 2011 at 9:58amQ2)Because sina, cosa, tana - g.p.

cos^2(a)=sina*tana=sin^2(a)/cosa

cos^2(a)=(1-cos^2(a))/cosa

cos^3(a)=1-cos^2(a)

**Answer this Question**

**Related Questions**

Trigonometry - Prove the following trigonometric identities. please give a ...

trig - I need to prove equality. a) (sina + cosa)^2 -1 / ctga - sinacosa = 2tg^...

Maths - Hi, can someone give me the answer to this question: secA-tanA=1/4. Find...

Math help again - cos(3π/4+x) + sin (3π/4 -x) = 0 = cos(3π/4)cosx...

Trigonometry. - ( tanx/1-cotx )+ (cotx/1-tanx)= (1+secxcscx) Good one! ...

math (trig) - i have some problems doing trig the first one is: Show that cos(x/...

maths - trigonometry - I've asked about this same question before, and someone ...

Trigonometry Help - Simplify: sin(x-y)cosy+cos(x-y)siny = (sinxcosy-cosxsiny)...

Trig....... - I need to prove that the following is true. Thanks (2tanx /1-tan^x...

calc - what is the derivative of sinx- cosy = 0 in its simplest form? I got to ...