题目
MAT135H5_F25_ALL SECTIONS 2.2 Preparation Check
多重下拉选择题
Suppose that with a certain phone company, an international long distance phone call from Canada to Brazil costs $0.90 for the first minute (up to and including 60 seconds), plus $0.50 for each additional minute or part of a minute. Note: "Part of a minute" means that if a new minute is started even just by one second, a full minute is charged. For example, a 5 min 1 sec phone call costs the same as a 5 min 50 sec phone call and the same as a 6 min 0 sec phone call. Suppose 𝐶 ( 𝑡 ) is the function that gives the cost of making a 𝑡 minute long phone call. On a piece of paper, sketch a graph showing 𝐶 ( 𝑡 ) (with 𝐶 on the 𝑦 -axis and 𝑡 on the 𝑥 -axis). Then use your graph to evaluate each of the following: (Write DNE for undefined.) 𝐶 ( 2.5 ) = [ Select ] DNE 1.9 1.4 2.4 2.9 𝐶 ( 4 ) = [ Select ] 3.4 1.9 2.9 2.4 DNE lim 𝑥 → 3.1 𝐶 ( 𝑡 ) = [ Select ] 1.9 1.4 2.9 2.4 DNE lim 𝑥 → 4 − 𝐶 ( 𝑡 ) = [ Select ] 2.4 1.4 2.9 1.9 DNE lim 𝑥 → 4 + 𝐶 ( 𝑡 ) = [ Select ] DNE 2.9 2.4 3.4 1.9 lim 𝑥 → 4 𝐶 ( 𝑡 ) = [ Select ] 1.9 2.9 DNE 3.4 2.4
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思路分析
We are given a cost function for an international call: C(t) = 0.90 for the first minute (up to 60 seconds), plus 0.50 for each additional minute or part of a minute. This means:
- If t is in (1, 2], the cost is 0.90 + 0.50*(number of additional minutes). For any t > 1, the number of additional minutes is ceil(t) − 1. So for t in (1, 2], C(t) = 0.90 + 0.50*(1) = 1.40.
- For t in (2, 3], C(t) = 0.90 + 0.50*(2) = 1.90.
- For t in (3, 4], C(t) = 0.90 + 0.50*(3) = 2.40.
- For t in (4, 5], C(t) = 0.90......Login to view full explanation登录即可查看完整答案
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类似问题
Consider this graph of the function 𝑓 ( 𝑥 ) . Which of the following statements are true and which are false? lim 𝑥 → 3 − 𝑓 ( 𝑥 ) = lim 𝑥 → 3 + 𝑓 ( 𝑥 ) [ Select ] False True lim 𝑥 → 1 𝑓 ( 𝑥 ) = 𝑓 ( 1 ) [ Select ] True False 𝑓 ( 𝑥 ) has a vertical asymptote at 𝑥 = 4 . [ Select ] False True 𝑓 ( 𝑥 ) has a vertical asymptote at 𝑥 = 6 . [ Select ] False True lim 𝑥 → 4 − 𝑓 ( 𝑥 ) = lim 𝑥 → 4 + 𝑓 ( 𝑥 ) [ Select ] False True lim 𝑥 → 4 𝑓 ( 𝑥 ) = ∞ [ Select ] True False lim 𝑥 → 6 𝑓 ( 𝑥 ) = ∞ [ Select ] False True The limit lim 𝑥 → 4 𝑓 ( 𝑥 ) exists, but lim 𝑥 → 6 𝑓 ( 𝑥 ) does not exist. [ Select ] False True
Consider the function 𝑓 ( 𝑥 ) = { 𝑥 2 + 1 𝑖 𝑓 𝑥 < 2 3 𝑖 𝑓 𝑥 = 2 7 − 𝑥 𝑖 𝑓 𝑥 > 2 . We aim to find out if 𝑓 ( 𝑥 ) has a discontinuity at 𝑥 = 2 , and if so, of what type. In order to do that, first find the following information: 𝑓 ( 2 ) = [ Select ] 5 3 2 7 lim 𝑥 ⟶ 2 − 𝑓 ( 𝑥 ) = [ Select ] 7 3 2 5 lim 𝑥 ⟶ 2 + 𝑓 ( 𝑥 ) = [ Select ] 5 7 2 3 Is 𝑓 ( 𝑥 ) continuous or discontinuous at 𝑥 = 2 ? [ Select ] discontinuous continuous If 𝑓 ( 𝑥 ) is discontinuous at 𝑥 = 2 , what type of discontinuity is it? [ Select ] f is continuous An infinite discontinuity A removable discontinuity A jump discontinuity
Consider this graph of the function 𝑓 ( 𝑥 ) . Which of the following statements are true and which are false? lim 𝑥 → 3 − 𝑓 ( 𝑥 ) = lim 𝑥 → 3 + 𝑓 ( 𝑥 ) [ Select ] False True lim 𝑥 → 1 𝑓 ( 𝑥 ) = 𝑓 ( 1 ) [ Select ] False True 𝑓 ( 𝑥 ) has a vertical asymptote at 𝑥 = 4 . [ Select ] True False 𝑓 ( 𝑥 ) has a vertical asymptote at 𝑥 = 6 . [ Select ] False True lim 𝑥 → 4 − 𝑓 ( 𝑥 ) = lim 𝑥 → 4 + 𝑓 ( 𝑥 ) [ Select ] True False lim 𝑥 → 4 𝑓 ( 𝑥 ) = ∞ [ Select ] False True lim 𝑥 → 6 𝑓 ( 𝑥 ) = ∞ False The limit lim 𝑥 → 4 𝑓 ( 𝑥 ) exists, but lim 𝑥 → 6 𝑓 ( 𝑥 ) does not exist. [ Select ] True False
MTH1010_09_10_3
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