Calculus Help! (Derivatives) Find the derivative of f(x)=arc sec(2x)
I thinks that's the answer 2/2x\[sqrt{4x^2-1}\]
-2/2xsqrt4x^2-1
@imer: would you please provide some framework for Mike_Petro so that he himself can answer this question. for example, you could type in\[\frac{ d }{ dx }\sin ^{-1}u=\frac{ \frac{ du }{ dx } }{ \sqrt{1-u^2} }\] and mention that u is itself a function of x.
explanation coming in a bit.
Yeah, the answer is great, but I'd like to be able to answer trig^-1 functions when test time comes! :) Thanks everyone in advanced
@imer: Thank you. Mind reversing the order? Explanation first. Formula second. Guide the student towards solving his/her own question, third.
@Mike_Petro: Glad to have your input. Tell the rest of us what you would like to know, or practice. We'll gladly help you solve your own math problems.
I usually go around giving the answer and then explain the concept . Some times the person knows the answer but wants to verify.
I'm doing a review for my exam a bit later, but a few problems are tripping me up like Integrals or exponential functions and trigonometric problems
@imer So I got the answer, is there a property or a set formula for these Trig^-1 functions?
Happy to help. Please post specific problems. Share your throughts about them. Separate what you know from what you don't. One of us will be delighted to respond.
I would recommend you to call them arc-trig functions and yes they are quite similar if you know the derivative of regular trig functions.
I will be explaining in a bit how they are derived.
Okay because I'm on another arc-trig function but it says not to use a calculator its sec(arctan(-3/5)) but since I cant use a calculator I'm assuming there is a set property sort of like cos x = sin x + c
lets start with simple one. \[y= \arcsin(x)\] If you are aware of implicit differentiation, then you can go around with this problem. \[y= \arcsin(x) \rightarrow \sin(y)=x\] Do you catch it?
So, arctan(x)=tan(y)?
Mike: This problem has nothing to do with integration, so your "cos x = sin x + c" is out of place here. Your topic here is "inverse trig functions." It's very important that you recognize that "artcan(-3/5)" is an ANGLE. It's possible, but totally unnecessary, to find that angle using a calculator. So scratch that. Instead, draw a picture of a triangle whose tangent is (-3/5):|dw:1403272082493:dw|
NO, \[\arctan(y)=x\] \[y=\arctan()\] It same as saying if arctan(x) gives me angle "y", then tan(y) will be give me "x"
@mathmale So I drew the triangle and the hypotenuse is sqrt(34) or 5.8, but how do I use it to find the answer? @imer OK so, if arctan(x)=y then tan(y)=x?
Its same as saying \[y=x^1/2\] is \[y^2=x\]
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