Question

If sin =1/2then show that 3cos -4cos^3=0

Answer 1

Answer:

Step-by-step explanation:

sen(x)=0.5

3cos(x)-4cos^3(x)=0

Remember:

cos^3(x)=cos(x)*cos^2(x)

3cos(x)-4(cos(x)*cos^2(x))=0

we have :

cos^2(x)=1-sin^2(x)

Then:

3cos(x)-4(cos(x)*(1-sin^2(x)))=0

sin^2(x)=(0.5)^2=0.25

3cos(x)-4(cos(x)*(1-0.25))=0

3cos(x)-4(cos(x)*(0.75))=0

Finally

3cos(x)-3cos(x)=0