Question

what is the value of (cos10°×cos20°×cos30°×....×cos120°)?​

Answer 1

Answer:

0

Step-by-step explanation:

Angles are in degree.

1) Since, we know that

$cos(90\degree) = 0;$

and

$|cos(x)| \leq 1$

2)

$=> (cos10\degree\times cos20\degree\times cos90\degree\times ....cos120\degree) \\ \\ => (cos10\degree\times cos20\degree\times 0 \times ....cos120\degree) \\ \\ => 0$

Similarly, Product of such sines is also 0 as

$sin(0\degree) = 0$.

Answer 2

Step-by-step explanation:

The value of Cos 120⁰ is - ½.