Question

If sinx=2cosx Then, what is the value of sin2x? pleaz tell

Answer 1

Square both sides
\[sin^2x = 4cos^2x \text{ }....(i)\]
\[or, 1-cos^2x = 4cos^2x\]


Now solve this to find out 'x'. Then use that to find out the value of sin2x.

Answer 2

but i get cosx=1/sqrt(5),then what?

Answer 3

so you can find sinx.

now, sin2x = 2*sinx*cosx

Answer 4

\[\sin2x=2sinxcosx\]

Answer 5

k!then

Answer 6

how would we find value of sinx?

Answer 7

k! thanx i got it

Answer 8

\[\sin2x=4\cos ^{^{2}}x\]