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Intersection of y=tan x and y=cos x
By Anonymous on Tuesday, October 17, 2000 - 04:59 pm:

Hi there everyone can someone please help
me with a problem from A-Level Maths, where
do the curves y=tan x and y=cos x cross and
give the co-ordinates. I am not sure about how
to go about this problem apart from using trial
and error and could really do with some help!!
Thanks.

By Kerwin Hui (P1312) on Tuesday, October 17, 2000 - 05:03 pm:

This is equivalent to solving:

tan x=cos x

First, note that cos x=0 is not a solution.

Multiply both side by cos x, giving:

sin x=cos2 x=1-sin2 x

This is a quadratic in sin x which you should be able to solve.

If you experience any problem please write back.

Kerwin

By Anonymous on Sunday, October 22, 2000 - 05:07 pm:

Thank you for your help I eventually worked out
the logic behind it all, and worked out the final
answer was 38.2 degrees which was correct
so thank you for your help.