SOLUTION: prove that: 1-2 cos (72°)= (2cos(72°))^2
Algebra
.Com
Question 1142797
:
prove that: 1-2 cos (72°)= (2cos(72°))^2
Answer by
math_helper(2461)
(
Show Source
): You can
put this solution on YOUR website!
Note that
RHS:
=
=
LHS:
=
=
RELATED QUESTIONS
prove that: 1-2cos (x)= 4(cos(x))^2
(answered by
math_helper
)
Prove: cos^2 z+1=2cos^2...
(answered by
Alan3354
)
cos^2-sin^2=2cos^2-1 prove that this is...
(answered by
stanbon
)
Could you please help me prove that 2cos(x)^2 - 1 =...
(answered by
Theo
)
Prove the identity: COS 2X-1/1+COS X = 2COS X -...
(answered by
lwsshak3
)
Prove that...
(answered by
Edwin McCravy
)
cos^2(x)+2cos(x)+1=0
(answered by
josgarithmetic
)
Prove that: 2cos^3 θ-cos θ/sinθ cos^2 θ-sin^3 θ= cot...
(answered by
solver91311
)
prove that : 2 (cos^2)A+ cos A - 1 =...
(answered by
stanbon,Alan3354
)