2sin^2a+5cosa=4 cosa=1/2
Xenoz:
u have to find the value of a or u have to prove cos a= 1/2
pt cosa=1/2
sry bt I actually hv not arrived till proffs....
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2sin²a +5cosa =4
or, 2(1-cos²a)+5cosa =4
or 2-2cos²a +5cosa =4
or, 2cos²a - 5cosa +2 =0
or, 2cos²a - 4cosa - CosA +2 =0
or, 2cosa(cosa - 2)-1(cosa - 2) =0
or, (2cosa - 1)(cosa - 2)=0
or, 2cosa - 1 =0
or, 2cosa =1
or, cosA =½... Proved...
Hope u like it...
or, 2(1-cos²a)+5cosa =4
or 2-2cos²a +5cosa =4
or, 2cos²a - 5cosa +2 =0
or, 2cos²a - 4cosa - CosA +2 =0
or, 2cosa(cosa - 2)-1(cosa - 2) =0
or, (2cosa - 1)(cosa - 2)=0
or, 2cosa - 1 =0
or, 2cosa =1
or, cosA =½... Proved...
Hope u like it...
mention not... my pleasure.
ur form
pp
??
pp means
question mark दे रहा था.. galti se pp hogaya
ur form means?
which ur native place
Bengal
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