Cos(A-B) = cosAcosB + sinAsinB
<span>
cos(</span>π/2 - θ) = cos(π/2)cosθ + sin(π/2)sinθ
π/2 = 90°
cos(π/2) = cos90° = 0. sin(π/2) = sin90° = 1
cos(π/2 - θ) = cos(π/2)cosθ + sin(π/2)sin<span>θ
</span>
= 0*cosθ + 1*sin<span>θ = </span>sin<span>θ
Therefore </span>cos(π/2 - θ) = sin<span>θ
QED </span>
Answer:
Step-by-step explanation:
a) A square is a rectangle. True
Reason: Property of Rectangle: (i) Opposite sides are equal and parallel. (ii) Each angle is 90 (iii) Diagonals are equal and bisect each other.
A square hold all these properties. A square is a rectangle.
b) A polygon with 21 sides has 432 possible diagonals. False
Reason: Number of diagonals of a polygon = 
n --> number of sides of a polygon.
=
= 189 diagonals
c) All three angles in an Isosceles triangle are equal. False
Reason: In an isosceles triangle, two angles are equal.
If three angles are equal, then that is an equilateral triangle.
d) The measures of the exterior angles of a nonagon, a nine-sided figure, have a sum of 360°. True.
Reason: The sum of measures of the exterior angles of any polygon is 360
Set this up as a ratio putting inches on top and feet on bottom. Then your first ratio would be 1/25 since 1 inch is the same as 25 feet. In between them goes an equals sign and the the other ratio has an x on top (because inches is what we are looking for) and the 1500 on the bottom. Cross multiply to solve for x:
1(1500) = x(25). Divide both sides by 25 to get 60
Answer:
Step-by-step explanation:
Sin58 = opp/hyp
Sin58 = CB/14
CB = 14 × sin58°
CB = 11.9cm
Answer:
22
Step-by-step explanation:
Range-find the largest number and subtract the smallest number from it
96-74