Consider the continous random variable, X, with pdf ?

We have : ∫ [-∞,∞] ƒ(x) dx = 1

∴∫ [2,4] ( k x³ ) dx = 1

∴ k [ ( x⁴ ) / 4 ] on [2,4] is = 1

∴ (k/4) [ 4⁴ - 2⁴ ] = 1

∴ (k/4) [ 256 - 16 ] = 1

∴ (k/4)(240) = 1

∴ k(60) = 1

∴ k = 1/(60) ............................. Ans.
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incredibly basic, only set the section under the curve to a million and remedy for ok: ok ? e? dx = e? – e° = e? – a million = a million (we set equivalent to a million) 0 for that reason e? = 2 and take ln of the two factors and get ok = ln 2

If you integrate f(x)dx from x=2 to x=4 you should get 1
and this will give k.. You should get 1/60.