Question

if SinA + CosA = 1/✓2, then find the value of 4SinA.CosA​

Answer 1

Answer:

LHS= sinA+cosA=1/√2

=(sinA+cosA)²=(1/√2)²

=sin²A+cos²A + 2sinAcosA= 1/2

=2sinAcosA= 1/2-1

=2(2sinAcosA)=(-1/2)2

=4sinAcosA=-1

HENCE THE VALUE OF 4SINA.COSA IS -1.