Answer:
15/4
Step-by-step explanation:
The answer to the questions
which means either
or
. The equation has no solution, since
is always bounded between -1 and 1. The second has one solution at
, and any number of complete revolutions will also satisfy this equation, so in general the solution would be
where
is any integer.
So you could choose
and
.
Answer:
ADC = 60
Step-by-step explanation:
180 - 120 = 60
120 + 120 + 60 + 60 = 360
From the double-angle identity,
we can rewritte our given equation as:
By factoring 2cosx on the left hand side, we have
This equation has 2 solutions when
From equation (A), we obtain
and from equation (B), we have
On the other hand, we can find one more solution from the original equation by substituting x=0, that is,
then, x=0 is another solution. In summary, we have obtained the following solutions:
However, the intersection of the last set is empty. So the unique solution is x=0 as we can corroborate on the following picture:
Therefore, the solution set is: {0}