Sin2(x) +cos(x)=1
from the relation: (sin2(x) +cos2(x) =1 )
so , sin2(x)=1-cos2(x)
by subs. in the main eqn.
1-cos2(x) + cos(x) =1
by simplify the eqn.
cos(x) -cos2(x)=0
take cos(x) as a common factor
cos(x)* (1-cos(x))=0
then cos(x)=0 && cos(x)=1
cos(x)=0 if x= pi/2
& cos(x) = 1 if x = 0 , 2*pi
so the solution is x= {0,pi/2 , 2*pi}
A nonagon has 9 sides, so n = 9
S = sum of the interior angles
S = 180*(n-2)
S = 180*(9-2)
S = 180*7
S = 1260
Answer is choice B
9x + 26 + 7x - 17 = 2x + (-3x) + 5x =
16x + 9 = 2x - 3x + 5x =
16x + 9 = 4x
9 = 4x - 16x
9 = - 12x
-9/12 = x
- 3/4 = x
