Prove that: cos^2 (45+A)+cos^2 (45-A)=1​

see explanation

Step-by-step explanation:

Using the cosine addition formula

cos(A ± B ) = cosAcosB ∓ sinAsinB

Then considering the left side

cos²(45 + A) + cos²(45 - A)

= [ cos45cosA - sin45sinA ]² + [cos45cosA + sin45sinA]]²

= [ cosA - sinA ]² + [ cosA + sinA ]²

= cos²A - sinAcosA + sin²A + cos²A + sinAcosA + sin²A

= cos²A + sin²A

= 1

= right side , then proven

Step-by-step explanation:

cos 2x=cos²x-sin²x=cos²x-(1-cos²x)=cos²x-1+cos²x=2cos²x-1

2cos²x=1+cos2x

cos²(45+A)+cos²(45-A)

cos (90-x)=sin x

cos (90+x)=-sin x

there are many solutions.

step-by-step explanation:

step 1: simplify both sides of the equation.

4x+6=4x^2+10x−4

step 2: subtract 4x^2+10x-4 from both sides.

4x+6−(4x^2+10x−4)=4x^2+10x−4−(4x^2+10x−4)

−4x^2−6x+10=0

step 3: factor left side of equation.

−2(2x+5)(x−1)=0

step 4: set factors equal to 0.

x=-5/2 or x=1

i found two solutions,   n = 2 • ± √3 = ± 3.4641

step-by-step explanation: