Asked by bhavesh

Integrate√tanx+√cotx

5 Answers

62
Lokesh Verma ·

I=∫(√tanx+√cotx)dx

let √tanx=t

dt = 1/(2√tanx)sec2x = {1+t4}/2t.dx

dx = 2t/(1+t4)dt

I=∫(√tanx+√cotx)dx

subst from above,

I=∫(t+1/t)2t/(1+t4)dt

I=∫2(t2+1)/(t4+1)dt

62
Lokesh Verma ·

now, divide numerator and denominator by t2

I=∫2(1/t2+1)/(t2+1/t2)dt

I=∫2(1/t2+1)/{(t-1/t)2)+2}dt

Now, t-1/t = m

differentiating, (1+1/t)dt = dm

Subst in equation above...

I = ∫2/{m2+2}dm

I =2/√2. tan-1(m/√2)

I = √2 tan-1(m/√2)

Where m=√tan x-√cot x

1
skygirl ·

this is a particular type of integrals.... even √tanxdx can be done in this way with some modifications....

then again for ∫x2dx/(x4+1) follows the same above rule with smple modifications.

33
Abhishek Priyam ·

wite the intefral as I=∫(sinx+cosx)/(sinx.cosx)1/2dx
Put sinx-cosx= t
and (sinx+cosx)dx=dt
2csox.sinx=1-t2

the given integral become

I=√2∫dt/(1-t2)1/2 = sin-1(t)+C

=sin-1(sinx-cosx)+c

62
Lokesh Verma ·

good work dude :)

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