若x²+ax-1/sin(x-1)的极限为2,x趋于3 ,求a 我感觉不对呀
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若x²+ax-1/sin(x-1)的极限为2,x趋于3 ,求a 我感觉不对呀
若x²+ax-1/sin(x-1)的极限为2,x趋于3 ,求a 我感觉不对呀
若x²+ax-1/sin(x-1)的极限为2,x趋于3 ,求a 我感觉不对呀
如果题目是x趋近于3,则a的结果=0,确实不对,但如果x是趋近于1的话,则结果a=0是对的.
①
2 = lim(x->3) x²+ax-1/sin(x-1) = 9+3a -1/sin2
a = [1/sin2 - 7]/3
②
2 = lim(x->3) [x²+ax-1]/sin(x-1) = [9+3a-1]/sin2 =[8+3a]/sin2
a = [2sin2 - 8]/3
③ 你那个题目是 x->1 啊...
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①
2 = lim(x->3) x²+ax-1/sin(x-1) = 9+3a -1/sin2
a = [1/sin2 - 7]/3
②
2 = lim(x->3) [x²+ax-1]/sin(x-1) = [9+3a-1]/sin2 =[8+3a]/sin2
a = [2sin2 - 8]/3
③ 你那个题目是 x->1 啊
lim(x->1) x²+ax-1/sin(x-1)
= lim(x->1) (x²-1)/sin(x-1) +ax/sin(x-1)
= lim(x->1) (x+1)[(x-1)/sin(x-1)] + ax/sin(x-1)
∵lim(x->1) (x+1)[(x-1)/sin(x-1)] =2
∴lim(x->1) ax/sin(x-1)= 0 ∴ a = 0
= 2
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