Math questions that i wasn't clear on~

hi guys, i've been doing some revision on my own, but i found some questions that i wasnt clear on how to do >_< can some1 please help~

ps: the boxed questions are the ones i nid help wid~ btw dis are calculater needed questions..(im surpose to be using calc to solve them)

thanks sooo much for your helppp >_<

6a) Differentiate.

6b) Normal line gradient = -1/m

For the sd question,

Use the formula given

Root of [(f(x^2)/f) - (Mean)^2]

in which f(x^2) / f will be [30(5^2) + 40(15^2) + 50(25^2) + ...] over total frequency

Hi,

For the last question, consider the use of the Binomial distribution.

Thanks!

Cheers,
Wen Shih

sorry 4 no reply, thx alot guys :D help alot on exams