The first two steps in determining the solution set of the system of equations, y = x2 – 6x + 12 and y = 2x – 4, algebraically a
2 answers:
You might be interested in
Answer:
(i) The name of the part of the circle, OQ is a radius
(ii) The radius of the sector QOR is 21 cm
Step-by-step explanation:
The given figure is a sector of the circle O
∵ Any sector of a circle formed from 2 radii and an arc
∴ OQ is a radius
(i) The name of the part of the circle, OQ is a radius
The rule of the length of an arc of a circle is L = × 2 π r, where
- α is the angle of the sector
- r is the radius of the circle
∵ The length of the arc QR is 22 cm
∴ L = 22
∵ The measure of the angle of the arc is 60°
∴ α = 60°
∵ π =
→ Substitute them in the rule above
∵ 22 = × 2 ×
× r
∴ 22 = r
→ Divide both sides by
∴ 21 = r
(ii) The radius of the sector QOR is 21 cm
The trick is to exploit the difference of squares formula,
Set a = √8 and b = √6, so that a + b is the expression in the denominator. Multiply by its conjugate a - b:
Whatever you do to the denominator, you have to do to the numerator too. So
Expand the numerator:
So we have
But √12 = √(3•4) = 2√3, so