Maths

[floral123]

Plz solve these simple quests...and kindly explain them secially the "dy" one!!
u can upload a doc file to make me understand easily or pm me!thanx

 

[xIshtar]

Hmm, well seeing as I'm doing AS Level, I can't remember any of the top questions, as for dy/dx, it is differentiating if you did not know.

I won't solve them for you, but simply explain how to differentiate with the help of an example.

If I had: x^3 + 2x^2 -3x + 3

You multiply by the original power, and then subtract one from it. So, it would become: 3x^2 + 4x -3.

The 3 is no longer written as it was previously x^0, which is 1. The 3x becomes 3 as it was previously 3x^1, which now becomes 3 as x^0 is 1.

Hope I helped!

 

[Mira Mohammed]

hey guys i need help in this question i'll write my answer and i f anyone can spot my STUPID mistake for sure integrate x(x+4)^0.5 and this should be done by substitution method i replaced (x+4)^0.5 by u and then i sqaured both sides to get an x value so that i can replace it u^2=x+4 then u^2-4=x consequently when deffrentiating the first equation dy/dx 0.5(x+4)^-0.5 and by replacing the values i will end up with u^2-4(u)0.5 du 2(u)^0.5 by multiplying the powers 2u^5/2 -8u and i'll integrate this getting 4/7 u^7/2 -4u^2 i guess iam not doing it in the right way something is wrong ! any help please