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Short maths question help pleasee:

The function f(x) is defined by f(x) = cos x for -pi < x < pi

Find the 2 values of x for which f(x) = 0

Okay so I know you first do these steps:
Cos x = 0
x = cos^-1 (0) = 1.570796327
What do you do next? show the steps pleaseee :smile:

Reply 1

Dream Eater

Well.. cos x is an even function (symmetric about the x-axis). So -1.570796327 is also an answer.

(Do you know what f(x) = cos x looks like on a graph? Because it is easier to see the solutions there, and you will also more easily see that the answers are

\frac{\pi}{2}, -\frac{\pi}{2}

Reply 2

PurpleRedSky

Neuron_16

You have it in radians which is good, picture cosx in you're mind and it is easier, symmetrical about the y axis.

If it is equals zero at+ pi/2 than it is also -pi/2 or -1.5707.... radians :o: