Find the polar equation of the conic with the focus at the pole, directrix x = -5, and eccentricity 2.
1 answer:
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Answer:
6 (assuming the units is in centimetres)
Step-by-step explanation:
Hi, hope this helps!
Method 1:
Calculate this shape as a trapezium. This is a trapezium because it has one pair of parallel sides. The way to calculate the area of a trapezium is this:
- Half the sum of the parallel sides
- Multiply the perpendicular height between them
In this case, 4 and 2 are parallel, so we add them together (4 + 2 = 6) then we divide by two (6 ÷ 2 = 3). Then we multiply our answer by the perpendicular length between the two parallel sides (assuming the side on the left is at a right-angle, 3 x 2 = 6).
Method 2:
Calculate this shape as a rectangle + a triangle. If you split the shape so the pointy bit on the right becomes a triangle and the left becomes a square, you can calculate the area without knowing the formula for calculating a trapezium (see above ^).
- Area of the square / rectangle = length x width = 2 x 2 = 4
- Area of the triangle = 1/2 x length x width = 2 x 2 x 1/2 = 4 x 1/2 = 4 ÷ 2 = 2
Then we add the two areas together (4 + 2 = 6).
I hope this helped and I wasn't waffling on :)
Bluey