Answer:
1) cos (3x)
2)
Step-by-step explanation:
Given expression:
cos(7x)cos(4x)+sin(7x)sin(4x)
By using the trigonometric identity
cos(a)cos(b) + sin(a)sin(b) = cos(a-b)
we have:
cos(7x)cos(4x)+sin(7x)sin(4x) = cos(7x - 4x)
= cos(3x)!
part 2:
tan (-π/12)
by using property tan(-x)= - tan(x)
=-tan(π/12)
= - tan(π/6 / 2)
Using tan(x/2) =
= -
cos π/6 =
= -
= -
= - 2+
=
!
10x ∠-20
x∠-20/10
x∠-2
this is your answer
hope it helps
Area of a triangle = 1/2bh
the height is 9 centimeters
multiply 36 with 2: 36 x 2 = 72
72/9 = 8
the length is 8 centimeters
hope this helps