Let <em>f(x)</em> be the sum of the geometric series,

for |<em>x</em>| < 1. Then taking the derivative gives the desired sum,

Answer:
57.4
Step-by-step explanation:
82.4 - 25 is too easy, a calculator can solve this.
Answer:
20 square units
Step-by-step explanation:
The figure shows a triangle whose;
- Base AC is 8 units
- Height is 5 units
We are supposed to get its area;
Area of a triangle is given by the formula;
Area = 0.5×b×h
Thus;
Area = 0.5 × 8 units × 5 units
= 20 square units
Hence, the area of the figure is 20 square units