SOLUTION: If sin(2x+20)=cos(40) find x Please help and show all steps. Thank you!

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Question 969466: If sin(2x+20)=cos(40) find x
Please help and show all steps. Thank you!

Answer by erica65404(394) About Me  (Show Source):
You can put this solution on YOUR website!
If sin%282x%2B20%29=cos%2840%29 find x

The cos(x) will always equal sin(90-x) which can be looked at as sin(y)=cos(x) where 90=x+y
To give you a few quick examples:
sin(60)=cos(30)
sin(10)=cos(80)
sin(90)=cos(0)
The numbers must always add up to 90.

so cos(40) in the problem is equal to sin(50).

sin%282x%2B20%29=sin%2850%29
or
2x%2B20=50
2x=30
x=15
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If you have questions, please email me at ericahigley@yahoo.com.