mcq...but need solve steep by steep
if cos^2 a-sin a = 1/4 then a = ?
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Solution:
cos²a-sina = 1/4
(1-sin²a) - sina = 1/4
4-4sin²a-4sina-1 = 0
=> 4sin²a+4sina-3 = 0
=> 4sin²a+6sina-2sina-3 = 0
=> 2sina(2sina+3)-1(2sina+3) = 0
=> (2sina-1)(2sina+3) = 0
since, Sina = -3/2 is not possible
=> Sina = 1/2
=> a = π/6 or 30° Ans.
cos²a-sina = 1/4
(1-sin²a) - sina = 1/4
4-4sin²a-4sina-1 = 0
=> 4sin²a+4sina-3 = 0
=> 4sin²a+6sina-2sina-3 = 0
=> 2sina(2sina+3)-1(2sina+3) = 0
=> (2sina-1)(2sina+3) = 0
since, Sina = -3/2 is not possible
=> Sina = 1/2
=> a = π/6 or 30° Ans.
Anonymous:
can u do 1st sum
yes
ok
ok
:)
2^55×2^60-2^97×2^18
thanks@sushant
plz do that question
most welcome
:)
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