what is the value of sin 150 in fraction?

sin(150)=
sin(90+60)=
sin(90)cos(60)+cos(90)sin(60)=
1*1/2+0*sqrt(3)/2=
1/2

Verify: (sinx+cosx)^2+(sinx-cosx)^2=2

 

cos^4a+cos^2a=1 ,prove is it identity or not

not an identity:
To disprove an identity we need only a single exception: 
 
and not 1 

:)

sec^4 a+sec^2 a=1 ,prove is it identity or not,thanks and regards

clearly not an identity try a=pi, substitution leads to 
2=1 
:)

prove: (cosx-secx)^2=tan^2(x)-sin^2(x)

 

which we rewrite as 

Computing Double Angles

If A is in Quadrant III and  , find the value of

so that


and so

Verify the basic identity. What is the domain of validity? cotθ = cosθcscθ

and it has the domain





:)

Verify: sin^4 (x)-cos^4 (x)=(2sin^2(x))-1

 


and then 

 

:)

Simplifying Basic Trig identities. tanx cotx + sinx secx

 

 

 

:)

verify the trig identity: (1+sinx)^2/cos^2(x) = (1 + sinx)/ (1-sinx )

 
For convenience we'll denote sin(x) as sinx. First we expand the numerator and rewrite the denominator: 
 
Using the difference of squares identity for the denominator... 
 
after cancelling... 

prove this equation: tan^2(x)-sin^2(x)=sin^2(x)tan^2(x)