sin(7a+9°)=cos2a. find a?
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Answered by
3
sin(7a+9°)=cos2a
sin{90°-(7a+9)}=cos2a
as,sin(90-∅)=cos∅
cos(7a+9)=cos2a
7a+9=2a
7a-2a=-9
5a=-9
a=-9/5
sin{90°-(7a+9)}=cos2a
as,sin(90-∅)=cos∅
cos(7a+9)=cos2a
7a+9=2a
7a-2a=-9
5a=-9
a=-9/5
kashish192:
why
ans not come
Answered by
2
Answer:
a = 9
Step-by-step explanation:
sin(7a+9) = cos2a
so, sin(7a+9) = cos(90-2a)
because cosa = sin(90-a)
so, 7a+9 = 90-2a
9a = 81
a =9
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