Sunday

September 21, 2014

September 21, 2014

Posted by **kc** on Sunday, July 24, 2011 at 8:47pm.

- pre cal 2 -
**Reiny**, Sunday, July 24, 2011 at 11:00pmsin4x=-2sin2x

2 sin2xcos2x = -2sin2x, ......... since sin2A = 2sinAcosA

cos2x = -1

2x = 180°, 360°, 540°, 720° which is π , 2π 3π, or 4π radians

x = 90° ,180°,270°, 360° which is π/2, π , 3π/2, or 2π radians

**Answer this Question**

**Related Questions**

Pre-Cal - Approximate the equation's soultions in the interval (o, 2pi). If ...

Pre-Cal(Please help) - Approximate the equation's soultions in the interval (o...

pre cal - Find all solutions in the interval[0,2pi),cos x/2-sinx=0

Pre CAL!! Please HELP - find the solutions of the equation that are in the ...

Pre CAL!! Please HELP - find the solutions of the equation that are in the ...

Math - Can I please get some help on these questions: 1. How many solutions does...

Trig - Find all the solutions in the interval [0,2pi). 2sin2x - sqrt(2) = 0 ...

Calculus - I need to find the exact solution to: 2sin2x = sqrt(x)on the interval...

Pre-cal - find all solutions of equation in [0, 2pi) 2 (sec x)^2 + (tan x)^2 -3...

pre cal 2 - Find all solutions in the unterval [0,2pi), cos x/2-sinx=0