The Student Room Group
thats correct, apart from a few typing errors with powers and stuff. I'm sure uve got it written down correct on paper.

(2cotx-1)(cotx+1)=0

2cotx = 1, cotx = 1/2
cotx = -1

Then you solve from there. I think 135 was the only value I got in the exam, and I got 100UMS, so that should be correct.
Reply 2
cosec4xcot4x=2cotx \large \mathrm{cosec}^4x - \cot^4x = 2 - cotx

Unparseable latex formula:

\large since \hspace 3 \mathrm{cosec}^2x = \cot^2x + 1



cosec4x=(cot2x+1)2 \large \mathrm{cosec}^4x = (cot^2x + 1)^2

Unparseable latex formula:

\large thus \hspace 3 (\cot^2x + 1)^2 - \cot^4x = 2 - \cot x



cot4x+2cot2x+1cot4x=2cotx \large \cot^4x + 2\cot^2x + 1 - \cot^4x = 2 - \cot x

2cot2x+cotx1=0 \large 2\cot^2x + \cot x - 1 = 0

Unparseable latex formula:

\large let \hspace 3 cot x = y



2y2+y1=0 \large 2y^2 + y - 1 = 0

(2y1)(y+1)=0 \large (2y - 1)(y + 1) = 0

Unparseable latex formula:

\large y = \frac{1}{2} \hspace3 y = -1



Unparseable latex formula:

\large \cot y \hspace3 = \frac{1}{2}, \cot y = -1



tany=2,tany=1 \large \tan y = 2, \tan y = - 1

Unparseable latex formula:

y = 63.4,243.4 \hspace4 y = 135, 315



Unparseable latex formula:

\large the \hspace3 range \hspace3 is \hspace3 90 < 0 < 180



x=135 \large x = 135
Reply 3
wow im impressed by me! lol thankx loads!
Reply 4
No problem i havent done any C3 in awhile tis good practice for moi :smile:.
Reply 5
your a neek