Question: What is the graph of the exponential function with base 2, y = 2^x, on the coordinate plane? Explain its characteristics, including the asymptote, increasing/decreasing behavior, and the key points.
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Question: In an arithmetic sequence, the fifth term is 18 and the ninth term is 42. Find the sum of the first 45 terms.
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Question: How many right-angled triangles can be formed if the lengths of two sides are 5 units and 12 units?