please answer my question
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Answered by
1
Answer:
sinB=1/2
B=30degrees
3cosB-4cos^3B
3cos30degrees-4cos^330degrees
3(√3/2)-4(√3/2)^3
3√3/2-3√3/2=0
(or)
3cosB-4cos^3B=cos3B
cos3(30)degrees=cos(90)degrees=0
hope it helps
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paidilokesh:
your solution is not correct (because cos90 not equal to zero ,cos90°=0). we should not forget units
yeah 90degrees I mean
but how to type it
units should be mentioned
that's none of my business
Answered by
1
Answer:
(a)0
Step-by-step explanation:
sinB=1/2
by using identity,
sin^2(B)+cos^(B)=1
1/4+cos^2(B)=1
cosB=√3/2
3(√3/2)-4(3√3/8)=0
3cosB-4cos^3B=0
(or)
given expression=cos3B=cos(3×30)°=cos90°=0
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