if cosec theta -sin theta = a cube and sec theta -cos theta = b cube then prove that a square.b sq(a sq + b sq) = 1

Given, cosecA – sinA = a 3

 
 
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  • 63

so here it is ..

cosecÓ¨ - sinÓ¨ = a3...

or (1 sin2Ó¨) /sinÓ¨ = cos2Ó¨ / sinÓ¨ = a3...

or a = (cos2Ó¨ / sinÓ¨)2/3 (i)

and

secÓ¨ cosÓ¨ = b3

or (1 cos2Ó¨) / cosÓ¨ = sin2Ó¨ / cosÓ¨ = b3

or b = (sin2Ó¨/cosÓ¨)2/3.. (ii)

Now lets put the last nail in this question's coffin Jby putting the values of a and b in the equation..

..a2b2(a2+ b2) ..

=(cos2Ó¨ / sinÓ¨)2/3(sin2Ó¨/ cosÓ¨)2/3 {(cos2Ó¨ / sinÓ¨)2/3+(sin2Ó¨/ cosÓ¨)2/3}

={ (cos2Ó¨ / sinÓ¨)(sin2Ó¨/ cosÓ¨)(cos2Ó¨ / sinÓ¨) }2/3+{ (cos2Ó¨ / sinÓ¨)(sin2Ó¨/ cosÓ¨) (sin2Ó¨ / cosÓ¨) }2/3

={cosÓ¨sinÓ¨(cos2Ó¨ / sinÓ¨) }2/3+{cosÓ¨ sinÓ¨(sin2Ó¨/ cosÓ¨) }2/3

=(cos3Ó¨)2/3+(sin3Ó¨)2/3

=cos2Ó¨+ sin2Ó¨ = 1

  • 2

Now.. hi sheryl.. after a long long tym... hw's ya?

let me tell u wt's my condition ryt nw... i have decided to drop a year and prepare fr the entrances again to get into a gud reputed college.... i'll be giving the boards too as i cud nt score much this yr... jst 78 % ... nd i am nt living in delhi .... i mean i am here in delhi ryt nw bt will fly to guwahati on 22nd where my dad's been tranferred... he's been there fr 2 yrs nd nw i'll be there too while rest of my family will be here .. i'll be preparing there nd come back to delhi again to give my boards and entrances... this is my condition so far... nd i am happy nd okay... u say... i saw ur complaint on my post... m srry yar bt had to go... nd i am nt sure if i'll come back to merit soon.. to bata kaisi chal rahi hai padhai... well tu masti kr yr... tera tym abhi msti krne ka hai... 11th me aa kr serious ho jana... hehe kidding ok then bbye frnd ... keep smiling :)

  • -13

hey in the 3rd and 7th line there is a minus sign b/w 1 sin(sq) theta nd b/w 1 cos(sq)theta

  • 6

nd 1 more thing eq(i) nd eq (ii) are fr a(sq) and b(sq)... nt fr 'a' nd 'b'.... nd then we put the values of a(sq) nd b(sq) in the eqna2b2(a2+ b2)... srry printing mistakes :P

  • 11

hiiiiiiiiiiiiiiiiiiiiiiiii.. ............!!!!

omg...itna kuchh ....btw...iski vajah se u left merit...?!....u no...ab mujhe lgta h....dat i shud post more Qs ....:PP n hope 2 c uh again....still lil shocked.....huh..!

  • 1
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