the value pi/2 is a solution to 4cos^2 (4x)-3=0
true or false?

Question

the value pi/2 is a solution to 4cos^2 (4x)-3=0
true or false?

campbell_st · Answer

ok... so solve it and you get 

4cos^2(4x) = 3

divde by 4

$$\cos^2(4x) = \frac{3}{4}$$

next take the square roots

$$\cos(4x) = \pm \frac{\sqrt{3}}{2}$$

now you should be able o solve from here as you have an exact value. 

when you get the 2 angles, divide them both by 4... to get x.

campbell_st · Answer

hope it helps

campbell_st · Answer

lol.... opps.... just substitute pi/2 into the equation. you don't need to solve it....

cutiecomittee123 · Answer

i already chose false on it as a wild guess to keep going. yikes.

campbell_st · Answer

so when substituting you get 

$$4 \cos^2(4 \times \frac{\pi}{2}) - 3 = 0$$

which is 

$$4\cos^2(2\pi) - 3 = 0$$

so find cos(2pi) 

and work from there.

campbell_st · Answer

so I'd say false is the correct choice.

cutiecomittee123 · Answer

thank goodness. lol Well I am stuggling a little with another, can you help again lol?