【纪念当年的帖子（2010）】Add Maths功课讨论区

永遠愛著許瑋倫

sry~  (5/2) logx

walrein_lim88

也是express y in terms of x
1) log y=5/2log x - 4
2)log y =(1/4)x + 7/4
請指教,萬分感激
永遠愛著許瑋倫 发表于 28-1-2010 11:49 PM

   

数学神

也是express y in terms of x
1) log y=5/2log x - 4
2)log y =(1/4)x + 7/4
請指教,萬分感激
永遠愛著許瑋倫 发表于 28-1-2010 23:49

这位，请注意一点
log y根本没有意思的
如果是log₁₀ y，那就是lg y吧了

考试这样写会危险下的

cryzord

有很pro的人在这里哦

superliong

请看看这题
Nora and Azman start working for two different companies at the same time.
a. Nora is paid RMp in the first year and her annual salary increases constantly by RMq every subsequent year . She is paid RM 38000 in the 9th year and her total salary for the 12 years is RM426000. Find the values of p and q.

b. Azman is paid RM28000 in the first year and his annual salary increases constantly by RM1500 every subsequent year . If Nora and his salaries are the same in the nth year , find the value of n .

乙劍真人

请看看这题

Nora and Azman start working for two different companies at the same time.
(a). Nora is paid RMp in the first year and her annual salary increasesconstantly by RMq every subsequent year . She is paid RM 38000 in the9th year and her total salary for the 12 years is RM426000. Find thevalues of p and q.

      T₉ = 38000
a + 8d = 38000 ---(1)

                   S₁₂ = 426000
(12/2) [2a + 11d] = 426000
            2a + 11d = 71000 ---(2)

Solve (1) & (2) simultaneously, a = 30000 & d = 1000

Hence, p = 30000 & q = 1000

(b). Azman is paid RM28000 in the first year and his annual salaryincreases constantly by RM1500 every subsequent year . If Nora and hissalaries are the same in the nth year , find the value of n .

Given a = 28000 & d = 1500

Tn = 28000 + (n - 1) 1500
    = 28000 + 1500n - 1500
    = 26500 + 1500n ---(3)

From (a) a = 30000 & d = 1000
Tn = 30000 + (n - 1) 1000
    = 30000 + 1000n - 1000
    = 29000 + 1000n ---(4)

Let (3) = (4) to find value n,

i.e. 26500 + 1500n = 29000 + 1000n
                         n = 5

Enceladus

Integration我有问题想发问，可以吗？

walrein_lim88

Integration我有问题想发问，可以吗？
Enceladus 发表于 1-2-2010 07:28 PM

    我在，问吧

walrein_lim88

Solve (1) & (2) simultaneously?
怎么做了啊
永遠愛著許瑋倫 发表于 1-2-2010 11:34 PM

    你可以用ELIMINATION 或 SUBSTITUTION

Enceladus

[img][/img]这题要按一下才看得到

walrein_lim88

[quote][/url][/img]这题要按一下才看得到
Enceladus 发表于 2-2-2010 03:41 PM
你要问什么？？

Enceladus

第四题和第五题，我做到很

Enceladus

我看着参考书，也做不出来。

walrein_lim88

第四题和第五题，我做到很
Enceladus 发表于 2-2-2010 05:51 PM

   

walrein_lim88

第四题和第五题，我做到很
Enceladus 发表于 2-2-2010 05:51 PM

Enceladus

我知道了，谢谢你的指导。还有一个问题：有时候他的graph没有给数目，要怎样才能找到他的数目？

walrein_lim88

我知道了，谢谢你的指导。还有一个问题：有时候他的graph没有给数目，要怎样才能找到他的数目？
Enceladus 发表于 2-2-2010 06:37 PM

    这个一定要用你之前的KNOWLEDGE了。。

Enceladus

什么knowledge，哪里一课的？

walrein_lim88

什么knowledge，哪里一课的？
Enceladus 发表于 2-2-2010 07:26 PM

    通常都是找ROOT的。。。QUADRATIC EQUATION

Enceladus

哦，我知道了，谢谢你