Saturday

April 19, 2014

April 19, 2014

Posted by **marie** on Monday, May 28, 2012 at 11:36pm.

cos 4x

2) Use half-angle identities to write the following expression, using trigonometric functions of x instead of x/4.

sin x/4

- trig -
**Steve**, Tuesday, May 29, 2012 at 3:56amcos4x = 2cos^2(2x)-1

= 2(2cos^2(x)-1)^2 - 1

just expand that

sin(x/4) = sqrt((1-cos(x/2))/2)

= sqrt((1-sqrt((1-cos(x))/2)/2

**Related Questions**

tRiG/ AlGeBrA - 1) Use double-angle identities to write the following expression...

Trig - How do you express sin4x as a trigonometric funcition of x using the ...

trig - Solving Trig Functions: How Do You Solve For Sin 7.5 Using Half-Angle and...

trig - Write the expression as the sine, cosine, or tangent of a double angle. ...

math-trig - Use the double angle identities to find sin2x if sinx= 1/square of ...

trig - A coil of wire rotating in a magnetic field induces a coltage E=20sin((...

trig identities - cos94 degrees cos18 degrees+ sin94 degrees sin18 degrees. ...

trig - Let Q be an acute angle such that sinQ=.6. Find the values of the ...

Math - Use the cofunction identities to write an expression that is equivalent ...

precal - im taking test need answer quick' use the sum and difference identities...