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Mathematics 10 Online
OpenStudy (samigupta8):

eliminate θ between cosecθ-sinθ=m and secθ-cosθ=n

OpenStudy (ash2326):

\[cosec\ \theta -\sin \theta=m\] @samigupta8 Please tell me what's the relation between sin and cosec?

OpenStudy (samigupta8):

don't u know it

OpenStudy (ash2326):

I do know, but I'm asking you so that you also take part in the process of answering

OpenStudy (samigupta8):

cotθcosθ=m

OpenStudy (ash2326):

Let me rephrase, how cosec x and sin x are related?

OpenStudy (samigupta8):

yes

OpenStudy (samigupta8):

1/sinθ-sinθ=m

OpenStudy (ash2326):

yes, so we'll get \[\frac{1-\sin^2 \theta}{\sin \theta}=m\] or \[\frac{\cos^2 \theta}{\sin \theta} =m\] or \[\cot \theta \cos \theta =m\]Can you simplify the second equation?

OpenStudy (ash2326):

\[\sec \theta -\cos \theta =n\]

OpenStudy (samigupta8):

sinθtanθ=n

OpenStudy (samigupta8):

then next

OpenStudy (ash2326):

Yes, I'm thinking

OpenStudy (samigupta8):

kk.....

OpenStudy (ash2326):

OK, let's multiply these two, we'd get \[\sin \theta \cos \theta= mn\] Now we'll square and add the two equations \[(cosec \theta -\sin \theta)^2+(\sec \theta -\cos \theta)^2=m^2+n^2\] \[cosec^2 \ \theta +\sin^2 \theta-1+\sec^2 \theta +\cos^2 \theta -1=m^2+n^2\] \[cosec^2 \ \theta+\sec^2 \theta +1-1-1=m^2+n^2\] Do you understand this?

OpenStudy (samigupta8):

ya...

OpenStudy (ash2326):

Next we'll write cosec in terms of sin and sec in terms of cos. Can you try? \[\cos \theta\sin \theta =mn\]

OpenStudy (samigupta8):

i m getting it as 1-m^2 n^2=(m^2-n^2)m^2 n^2

OpenStudy (ash2326):

Check again, I got \[(m^2+n^2+1)(mn)^2=1\]

OpenStudy (samigupta8):

i got it as (mn)^2+(mn)^2(m^2+n^2=1

OpenStudy (samigupta8):

yeasss... u are ryt

OpenStudy (ash2326):

Interim steps are \[\frac{1}{\sin^2 x}+\frac{1}{\cos^2 x}-1=m^2+n^2\] \[\frac{\cos^2 x+\sin^2 x}{\cos^2 x \times \sin^2 x}-1=m^2+n^2\] \[\frac{1}{(mn)^2}-1=m^2+n^2\]

OpenStudy (samigupta8):

btt answer is given as(m^2n)^2/3+(mn^2)^2/3=1

OpenStudy (samigupta8):

how is this ans coming

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