Calculus III. Need answers for 1, 2 & 3

1. Given a 1"[ order di'erential equation, Euler's method will provide an overestimate when the solution curve is concave (3 points}. 2. Compute the exact sum of the following innite series (5 points): m 111 3. The following sequence is convergent. Find the limit (5 points). a\" = cos(2'\") + 2 arctanCN) - sin (mm7') 12N+5