Posted by . on Tuesday, April 20, 2010 at 4:03pm.
Verify the identity.
sin2x/cosx + sinx = 2sinx
Solve for all values of x:
If f(x)=cos1/2x-sin2x find the value of
- Trigonometry - Reiny, Tuesday, April 20, 2010 at 5:33pm
the first identity is not correct
LS = sin2x/cosx + sinx
= 2sinxcosx/cosx + sinx
= 2sinx + sinx
= 3 sinx
You have RS = 2sinx
You probably typed this incorrectly and really meant
if so, let cosx = y, then our equation becomes
6y^2 - 7y - 3 = 0
(2y - 3)(3y + 1) = 0
y = 2/3 or y = -1/3
cosx = 2/3 or cosx = -1/3
for cosx = 2/3, x is in I or IV
x = 48.2 or 311.8°
for cosx = -1/3, x is in II or III
x = 109.5 or 250.5°
for the last one, sub in x = π
Answer this Question
- Trig - Verify the identity: tanx(cos2x) = sin2x - tanx Left Side = (sinx/cosx)(...
- maths - hey, i would really appreciate some help solving for x when: sin2x=cosx ...
- math - solve each equation for 0=/<x=/<2pi sin^2x + 5sinx + 6 = 0? how do ...
- maths - by equating the coefficients of sin x and cos x , or otherwise, find ...
- Math please help quick - Which of the following are identities? Check all that ...
- Math - prove identity Sin2x - sinx/cosx + cos2x= sinx/cosx + 1
- check math - Here are my answers. Can you check if I got the right answers? ...
- Trig - If secx = 8 and -pi/2 < x < 0, find the exact value of sin2x Use ...
- Trigonometry - Simplify #1: cscx(sin^2x+cos^2xtanx)/sinx+cosx = cscx((1)tanx)/...
- math - Prove the identity (sinx+cosx)^2 = 1+sin2x Thank you