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If the sides of a DeltaA B C\ are a=4,...

If the sides of a ` DeltaA B C\ ` are `a=4,\ b=6\ a n d\ c=8,` show that `4cosB+3cos C=2.`

Text Solution

Verified by Experts

We have,

`a=4, b=6, c=8`

Therefore,

`cos B=frac{a^{2}+c^{2}-b^{2}}{2 a c}`

`=frac{16+64-36}{2 times 4 times 8}`

...
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RD SHARMA-SINE AND COSINE FORMULAE AND THEIR APPLICATIONS-Solved Examples And Exercises
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  3. If the sides of a DeltaA B C\ are a=4,\ b=6\ a n d\ c=8, show that 4...

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  13. In a A B C , prove the following : In a DeltaA B C ,\ if\ a=5, m\ b=...

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  14. In a DeltaA B C , prove the following :\ If\ a=sqrt(2),\ b=sqrt(3)\ a...

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  15. In a DeltaA B C , prove the following : The sides of a triangle area ...

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  17. In a DeltaA B C , prove the following : c\ (acosB-bcosA)=a^2-b^2dot

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  18. In a DeltaA B C , prove the following : (c^2+b^2-a^2)tanA=(a^2+c^2-b^...

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  19. In a Delta A B C , prove the following : (c-b\ cos A)/(b-c\ cos A)=(c...

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  20. In a Delta A B C , prove the following : \ a(cos B+cos C-1)+b(cos C+c...

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