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Ravi
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Ravi asked in Education & ReferenceWords & Wordplay · 8 years ago

CosA=1/under root2, SinA= -1/under root 2.?

find the value of A. thanks

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  • Anonymous
    8 years ago
    Favorite Answer

    A is in the 4th quadrant from the info given. So A=7π/4. Verify: sin(7π/4)=sin (2π-π/4)=sin2πcosπ/4-cos2πsinπ/4=

    -sinπ/4=

    -1/√2, cos(7π/4)=cos(2π-π/4)=

    cos2πcosπ/4+sin2πsinπ/4=cosπ/4=1/√2.

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