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2 years ago

Sina=3/5 find cos2a

Mathematics

1 answer:

yarga [219]2 years ago

6 0

Answer:

$\huge \purple{\therefore \cos2a} \orange{= }\red{\frac{7}{25} }$

Step-by-step explanation:

$\because \cos2a =1 - 2 { \sin}^{2} a \\ \\ \therefore \cos2a =1 - 2 \bigg( { \frac{3}{5} }\bigg) ^{2} \\ \\\therefore \cos2a =1 - 2 \times \frac{9}{25} \\ \\\therefore \cos2a =1 - \frac{18}{25} \\ \\\therefore \cos2a = \frac{25 - 18}{25} \\ \\ \huge \purple{\therefore \cos2a} \orange{= }\red{\frac{7}{25} } \\ \\$

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3 years ago

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Leno4ka [110]

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3 years ago

Sina=3/5 find cos2a​

Sina=3/5 find cos2a