help please number 2..

Question

marcelie · Answer

attachment

marcelie · Answer

@agent0smith

marcelie · Answer

can you please help me.. i have no idea

marcelie · Answer

can someone pleaseee help me D:

ganeshie8 · Answer

Yiu would have some idea if you read the problem completely

ganeshie8 · Answer

It tells you what to substitute 
Have you tried that ?

marcelie · Answer

yes i did that  but im having trouble identifying the identities or what to do next

ganeshie8 · Answer

what exactly are you stuck at ?

ganeshie8 · Answer

marcelie · Answer

$$\int\limits_{}^{}\frac{ 8\tan ^3\theta }{ \sqrt{(4 \sec^2\theta-1)+4}}$$

marcelie · Answer

is it something like this ?

marcelie · Answer

@Astrophysics

ganeshie8 · Answer

I'm on mobile 
Can't latex

ganeshie8 · Answer

Numerator looks okay
Denominator doesn't

ganeshie8 · Answer

First simply plugin the given substitution

Doing multiple operations in a single step is a sure way to cinfusion

astrophysics · Answer

Yeah I agree with ganeshie, lets just start by plugging in what they want you to, can you try that

astrophysics · Answer

$$x = 2 \tan \theta, -\pi/2 <  \theta < \pi /2 \implies dx = 2\sec^2 \theta d \theta $$ now try your substitution

astrophysics · Answer

$$\int\limits \frac{ 8 \tan^3 \theta }{ \sqrt{4\tan^2 \theta+4} }2\sec^2 \theta d \theta $$ right?

marcelie · Answer

oh yeh

marcelie · Answer

got it thanks everyone