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Maclaurin Series - HELP PLEASE!!

Hey guys,

I'm stuck trying to find Maclaurin Series for sec(x).

So far I have recogninsed it's 1/cox(x) so its 1/(1 - x^2/2!=x^4/4...)

What do I do next?

Differentiate?

i personally do maclaurin series manually, so i do sec(x), then do x lots of the derivative of sec(x), then x^2/2 lots of the second derivative and so on

Reply 3

Sinfire

Alternatively, you could equate that to a general polynomial (a0 + a1*x + a2*x^2 + ...), then multiply through and equate the coefficients on both sides. You could then compute the coefficients by solving the systems of equations.

(edited 8 years ago)

Reply 4

hindjain

So can I set (1 - x^2/2! + x^4/4!.... ) × (1 + ax^2/2! + bx^4/4!...) = 1

And then solve for the polynomial because I know that cosx is even so secx is even and therefore there should be no odd powers in the series... i think?