(R + RCos (2,57 (20)) = 12), How to solve for R?

1 Answer
Tony B
Mar 29, 2016

This solution is based on #cos(2.57xx20)#
#R~~7.390# to 3 decimal places
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#R=12/(1+cos(2.5720)) ~~6.003# to 3 decimal places

Explanation:

Given: #R+Rcos(2.57(20))=12#

Factor out the R giving

#R(1+cos(2.57(20))=12#

Divide both sides by #(1+cos(2.57(20))# giving

#R xx (1+cos(2.57(20)))/(1+cos(2.57(20))) =12/(1+cos(2.57(20))) #

But #(1+cos(2.57(20))) /(1+cos(2.57(20))) =1# giving

#R=12/(1+cos(2.57(20))) #

#R~~7.390# to 3 decimal places

This solution is based on #cos(2.57xx20)#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Or, if you meant:
#R=12/(1+cos(2.5720)) #

#R=6.003# to 3 decimal places

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