SOLUTION: if sinx + cosx = 4/3 then sin2x = ?

Question 1064981: if sinx + cosx = 4/3 then sin2x = ?
Answer by ikleyn(52818) (Show Source): You can put this solution on YOUR website!
.

As you know (or must to know)

sin(2x) = 2*sin(x)*cos(x).


Now trace my steps:


if  sinx + cosx = 4/3  then   = ,   or

 = ,

1 + 2*sin(x)*cos(x) = ,

2*sin(x)*cos(x) =  = ,

Therefore,

sin(2x) = .

Solved.

RELATED QUESTIONS
If sinx + cosx = 3/4 find sinx -... (answered by Alan3354)

If tanx=-1/3 ; cosx>0 then sin2x= cos2x=... (answered by stanbon)

If x is in quadrant I and sinx-cosx=1/3, then the value of sinx+cosx is… A)4/3... (answered by math_tutor2020)

sin2x/sinx - cos2x/cosx = secx Prove this identity starting with sin2x/sinx -... (answered by Alan3354)

if u= int (f(sin2x)sinx)dx on [0 ,pi/2] and v= int (f(cos2x)cosx)dx on [0 ,pi/2] then... (answered by ikleyn)

sinx=3/4, tanx=9/2... (answered by ewatrrr)

(sinx+cosx)�=3/4.Find... (answered by greenestamps)

(sinx+cosx)�=3/4.find... (answered by greenestamps)

Cosx-4=... (answered by Fombitz)