Question

If sin A = 3/4 and 0° < A < 90°, then the value of cos 2A = _________​

Answer 1

Answer:

sin A = 3/4 = P/H

Base of triangle

By Pythagoras theorem

then,

$b {}^{2} = h { }^{2} - p {}^{2}$

b^2 = 4^2 -3^2

b^2 = 16-9

b^2= 7

b=

$\sqrt{ 7}$

cos 2 A =

$( \sqrt{7 } ) \div 4$

$(\sqrt{7}) {}^{2} \div 4 {}^{2}$

cos 2 A = 7/16

Answer 2

Answer:

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