Grade 11Trigonometry
Sin5xcos3x..plxz help me to get out of this question...answer fast....
Sin5xcos3x..plxz help me to get out of this question...answer fast....
2 Answers
Saurabh Koranglekar
Approved Tutor Answer6 Years agoDear student
Sin ( a+b)+ sin ( a-b)
= 2 sin a cos b
On simplification of the question
Sin 2x = sin 4 x
2sin x cos x = 2 sin x. Cos x. Cos 2x
Cos 2x = 1
Now you can solve further
Regards
Sin ( a+b)+ sin ( a-b)
= 2 sin a cos b
On simplification of the question
Sin 2x = sin 4 x
2sin x cos x = 2 sin x. Cos x. Cos 2x
Cos 2x = 1
Now you can solve further
Regards
Arun
Approved Tutor Answer6 Years agoDear student
multiply by 2 in LHS and RHS
then it becomes after using the formula of 2 sinAcosB
sin 8x + sin 2x = sin 8x + sin 4x
hence sin 2x = sin 4x
sin2x (1 – 2 cos2x) = 0
hence sin2x = 0 or cos2x = ½
2x = n* pi or 2x = 2 n* pi ± pi/3
x = n * pi/2 or x = n * pi ± pi/6
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