and how would i go about working out the inverses of trig functions if i didnt already know them?
First off: [tex]\sec^2\theta=1+\tan^2\theta[/tex]
Vague question but I suspect you mean do the following.
x = 1 / cos^2(y)
sqrt(x) = 1/cos(y)
1/sqrt(x) = cos(y)
y = arccos(1/sqrt(x))
Now that's only half the solution, the most important part is working out the domain and range for which this inverse makes sense.
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