Mathematics · 2020
JEE Main · 9 January 2020, Shift 1 · Q69
The value of cos^3((π)/8) · cos ((3 π)/8)+ sin^3((π)/8) · sin ((3 π)/8) is:
The value of
$$\cos ^3\left(\frac{\pi}{8}\right) \cdot \cos \left(\frac{3 \pi}{8}\right)+\sin ^3\left(\frac{\pi}{8}\right) \cdot \sin \left(\frac{3 \pi}{8}\right)
$$
is :
Official answer
(3)
$\displaystyle \frac{1}{2 \sqrt{2}}$
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JEE Main 2020 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.