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Core 3 Integration by subs and expressing the answer

Integrate 1/(1+2tanX)^2 cos^2X dX via substitution

I got the answer as -1/2 (1+2tanX)^-1 + C

Which, I THINK is the same as the one in the mark scheme as shown.

Will I get full marks? Usually it says in the MS accept other forms but it does not here even though the Q never asked for a form anyway.. Integration via subs.png

Reply 1

ghostwalker

Original post by MSI_10

I got the answer as -1/2 (1+2tanX)^-1 + C

Which, I THINK is the same as the one in the mark scheme as shown.

Will I get full marks?

Yes, it's the same.

If they don't give you full marks, I'd challenge it.

Reply 2

Lerkio

It's actually not the same. You've got -1/2 at the beginning so you don't need the ^-1

Reply 3

ghostwalker

Original post by Lerkio

It's actually not the same. You've got -1/2 at the beginning so you don't need the ^-1

It's slightly ambiguous notation. Given the space between the 2 and the (, I interpret the OPs formula as -1/2 x (1+2tanX)^-1, in which case the ^-1 is required.

It is preferable to use LaTex on this forum to avoid situations like this.

PS: This thread is over 4 years old!