math question

[Atl21]

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Hi,

Can anyone help me integrate this : Integrate (sinx/cos^2x)dx? Thanks

 

[Knickerbocker]

Hi,

Can anyone help me integrate this : Integrate (sinx/cos^2x)dx? Thanks

No promises on correctness, but maybe this?

sin x / cos x = tanx, so

sinx / (cos x)^2 =

tan x / cos x

1 / cos x = sec x, so

we get: tan x sec x

the integral of tan x sec x (dx) is defined to be sec x + C

 

[Atl21]

i do'n t understand how the integral of tanxsecx equal secx + c

 

[Knickerbocker]

i do'n t understand how the integral of tanxsecx equal secx + c

The integral of (sec x tan x) dx has a rule assigned to it. Your book should have a list. If not, look here:

http://people.hofstra.edu/stefan_waner/RealWorld/trig/trig4.html

It's the fifth one in the table of antiderivative rules.

 

[fenixtnlfan]

Does the PCAT usually cover this hard of calculus? Well, not hard but having to know all the rules.

 

[binghamkid]

No it usually doesn't.

The calculus they expect you to know is generally first semester calculus with enough integration from the second semester. That sort of question is doable, but the question isn't doable without knowing the rule; they don't expect you to memorize rules to that sort of degree. Of course, if you did have it memorized you'd have the advantage, but you'd seriously only see 1 question like that on any given exam if any at all.

 

[PharmHopeful3]

on the last pcat they did ask you to integrate a weird trig function...2 being multiplied, i think. i was quite shocked b/c i didnt remember the math being that difficult the first time.