Homework Help: Trig

Posted by Ashley on Saturday, April 14, 2007 at 1:57pm.

Verify the identity:
tanx(cos2x) = sin2x - tanx

Left Side = (sinx/cosx)(2cos^2 x -1)
=sinx(2cos^2 x - 1)/cosx

Right Side = 2sinx cosx - sinx/cosx
=(2sinxcos^2 x - sinx)/cosx
=sinx(2cos^2 x -1)/cosx
= L.S.

Q.E.D.

No one has answered this question yet.

Answer this Question

Related Questions

Pre-Calc - Trigonometric Identities Prove: (tanx + secx -1)/(tanx - secx + 1)= ...
Trigonometry Check - Simplify #3: [cosx-sin(90-x)sinx]/[cosx-cos(180-x)tanx] = [...
Math - Im really struggling with these proving identities problems can somebody ...
Trigonometry. - ( tanx/1-cotx )+ (cotx/1-tanx)= (1+secxcscx) Good one! ...
Math 12 - Simplify #1: cscx(sin^2x+cos^2xtanx)/sinx+cosx = cscx((1)tanx)/sinx+...
Trigonometry - Simplify #1: cscx(sin^2x+cos^2xtanx)/sinx+cosx = cscx((1)tanx)/...
Math - Proving identity (sinx+tanx)/(cosx+1)=tanx RS: (sinx+(sinx/cosx))/(cosx+1...
Mathematics - Trigonometric Identities - Prove: (tanx)(sinx) / (tanx) + (sinx...
Math - I'm only aloud to manipulate one side of the problem and the end ...
Mathematics - Trigonometric Identities - Prove: sinx + tanx = tanx (1 + cosx) ...

For Further Reading

First Name:
School Subject:
Answer: