find the value of A if: 2 cos^2A+cosA-1=0
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Answered by
4
hey.............
The given equation is .
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this part of the solution is in the image
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When cos A = 1, we have
A = 0°
When cos A = , we have
A = 60°
Thus, the solution of the given equation is 0° or 60°.
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2cos2A-3cosA+1=0
2cos2A-2cosA-cosA+1=0
2cosA(cosA-1)-1(cosA-1)=0
(2cosA-1)(cosA-1)=0
(2cosA-1)=0
cosA=1/2
therefore , A=45 degree
(cosA-1)=0
cosA=1
therefore,A=0degree
so,the value osf Ais 0degree or 45degree
therefore A=45
The given equation is .
=======≠======================≠==
this part of the solution is in the image
==================================
When cos A = 1, we have
A = 0°
When cos A = , we have
A = 60°
Thus, the solution of the given equation is 0° or 60°.
/////////////////////////////////////////////////////
2cos2A-3cosA+1=0
2cos2A-2cosA-cosA+1=0
2cosA(cosA-1)-1(cosA-1)=0
(2cosA-1)(cosA-1)=0
(2cosA-1)=0
cosA=1/2
therefore , A=45 degree
(cosA-1)=0
cosA=1
therefore,A=0degree
so,the value osf Ais 0degree or 45degree
therefore A=45
Attachments:
dhakatanishqddun:
////////after these
check it out
see the second image dear riya
just take A as x
ok
Riya Bashisth
thank you so much
now mark it as brainlist
good to help u Riya
:-)
Answered by
2
step by step explanation
here in such questions u first have to use the hit and trial method if u get success then no problem if dont then we solve this but this question is solved by hit and trial method lets consider with me
2cos^2A+cosa=1
now putting A=60°
u will find it is satisfying our equation so A will be 60°
hope u find it helpful if yes then mark it as brianliest.:D:);):-)
here in such questions u first have to use the hit and trial method if u get success then no problem if dont then we solve this but this question is solved by hit and trial method lets consider with me
2cos^2A+cosa=1
now putting A=60°
u will find it is satisfying our equation so A will be 60°
hope u find it helpful if yes then mark it as brianliest.:D:);):-)
is there any other way to solve this problem
hmm
but in all the case at last u have to use hit and trial
means u should remember the ratio value at diiferent angles
ok can u please let me know the other way to sove it
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