# Thread: two tricky trig problems

1. ## two tricky trig problems

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1) solve: cos2x-cos6x=0

and

2) The number of hours daylight in Detroit on day 't' ( with t = 0 on January 1st) of a non-leap year is given by:
d(t)=3sin[(2π/365)(t-80)]+12

a) What days have exactly 11 hrs. of daylight
b)What day has a maximum amount of daylight

if you thought those were easy try

Solve: X (to the 3/8) - (square root of negative one)(square root of 3)=3

2. Originally Posted by rutheada000
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1) solve: cos2x-cos6x=0

[snip]
=> cos(2x) = cos(6x).

Note that the general solution to cos(A) = cos(B) is:

A = B + 2 n pi and A = -B + 2 n pi

where n is an integer .....