Ask Experts Questions for FREE Help !
Ask
    susus's Avatar
    susus Posts: 138, Reputation: 2
    Junior Member
     
    #1

    Nov 14, 2010, 12:40 PM
    the derivative of two functions
    it looks easy but, I do not know what I did wrong:
    what is the derivative of f(x) = cosx -1/3(cos^3 x )
    the answer is -sin^3 x
    while I got -sinx+cos^2 x * sinx !

    and also with this :
    f(x) = 1/ (x+ sqr(x^2 +1))

    galactus's Avatar
    galactus Posts: 2,271, Reputation: 282
    Ultra Member
     
    #2

    Nov 14, 2010, 12:53 PM

    Your solution is correct. Only in another form.

    wutang69's Avatar
    wutang69 Posts: 1, Reputation: 1
    New Member
     
    #3

    Dec 5, 2010, 01:06 PM
    My word! Have you never heard of trigonometric identities? Here's a link so you never run into that problem again. http://www.clarku.edu/~djoyce/trig/identities.html

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

How to solve trig functions applications for advanced functions? [ 2 Answers ]

A point on the ocean rises and falls as wave pass Suppose that a wave passes every 4 s, and the height of each wave from the crest to the trough in 0.5 m. a) how do we graph the height of the point relative to tis average height for a complete cycle, starting at the crest of a wave. And how do...

Composition Functions and Inverse Functions [ 3 Answers ]

Wow! These things are boogers! :eek: any way to make these things easier?

Derivative for dt/dx [ 5 Answers ]

150000(0.00625/1-(0.99378)^12t) solve for dt/dx

Derivative of exponential functions [ 1 Answers ]

Hi there, I'm having difficulties with this particular question The function h: R- > R, h(t)=(t^2+at+10) e ^ - t, where a is a real constant, has a derivative h'(t) = (-t^2 + (2-a)t + (a-10))e^ -t. Find the values of a such that I) the graph of y=h(t) has exactly on stationery point. ii)...

Derivative again [ 8 Answers ]

Please help me with this one also... The perimeter of a window, made in the shape of a semicircle on a rectangle, is 4m. Find its dimensions if the area is to be a maximum?


View more questions Search