Math Is Fun Forum

timone5666

Member

Registered: 2009-03-01

Posts: 2

Need quick help on Trig proofs

Verify the identity: tan(π/4-θ) = (1-tanθ) / (1+tanθ)

Now I hate these proofs. It is easy in the exercise but I have this take home quiz which is only 5% of my grade but I would love to learn to do these professionally could anyone help me do these? I have the remaining questions below

Verify the identity: Cos(4x) - Cos(2x) / 2sin(3x) = -sin(x)

Verify the identity: 2cos(2x-2) / sin(2x) = cot(x) - sec(x)Csc(x) - tan(x)

Write an expression that is equivalent to Sec(2tan-¹x) Yet that does not use trig functions. Assume that the variable represents a positive value.

Give all radian solutions to tan²5x = 3

Solve 1+Cos(2x) = 2Sin²(2x) for x, where 0≤x<2π

Give all degree solutions to cos(7x)cos(2x)+sin(7x)sin(2x)=½

Eliminate the parameter t: x=4+8Csc(t)  y=7-8Cot(t)

Verify the identity [Cos(x/2)-sin(x/2)]² = 1-sin(x)

I would be forever grateful if someone could help me here. Everyone around me can't even count to ten and work as dishwashers ;p

Last edited by timone5666 (2009-03-01 11:11:11)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Need quick help on Trig proofs

Hi timone5666;

The first one is easy. I am not sure what grouping you want but,

Neither of those are identities.

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