-12 would fall into integers and real numbers.
-12 is not a natural number because it is negative.
-12 is not irrational because it can be transferred into a fraction,
.
I think so the answer is 1/4
Yes, it is true (I’m pretty sure, same shape etc)
<A +<B + < C =180° ==>(5x+6) + (2x+1) + (6x+4) = 180°
13x = 180°-11° ==> 13x 169° and x =169/13 =13°
Answer:
cos(a + b) = 
Step-by-step explanation:
cos(a + b) = cos(a).cos(b) - sin(a).sin(b) [Identity]
cos(a) = 
cos(b) = 
Since, terminal side of angle 'a' lies in quadrant 3, sine of angle 'a' will be negative.
sin(a) = 
[Since, sin(a) = 
]
= 
= 
Similarly, terminal side of angle 'b' lies in quadrant 2, sine of angle 'b' will be negative.
sin(b) = 
= 
= 
By substituting these values in the identity,
cos(a + b) = 
= 
= 
=
Therefore, cos(a + b) =
