Math, asked by muskan65282, 3 months ago

sin10°sin50°sin70°=1/8. prove it​

Answers

Answered by annunavneetsinghal
2

Step-by-step explanation:

sin10°sin50°sin70°=1/8. prove it

Answered by slm29112004
3

Step-by-step explanation:

sin10. sin50. sin 70

sin10. sin(60-10).sin(60+10)

1/2(2sin10.sin50.sin70)

we know that 2sinA.sinB=cos(A-B).COS(A+B)

Then1/2(2sin10.sin50, sin70) =1/2(sin10(cos 20-cos120)

And cos 20=cos(90+30)=1/2

so1/2(sin10(cos20+1/2)

1/2sin10.cos20+1/4sin10

1/4(sin30-sin10)+1/4sin10

1/4sin30

1/4*1/2

1/8(proved)

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