Question

If sinx = 2cosx, the value of sin2x is
(A) 1/3
(B) 2/3
(C)-4/3
(D) 4/5
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Answer 1

HELLO DEAR,

given:- sinx = 2cosx

=> tanx = 2 = p/b

by Pythagoras theorem,

h = √5

so, sinX = 2/√5 & cosX = 1/√5

as, we know:- sin2∅ = 2sin∅cos∅

therefore, sin2X = 2sinXcosX

=> 2 * (2/√5) * (1/√5)

=> 4/5

hence, option (D) is correct

I HOPE IT'S HELP YOU DEAR,

THANKS