A vector ` vec O P` is inclined to `O Xa t45^0a n dO Ya t60^0` . Find the angle at which ` vec O P` is inclined to `O Zdot`

Explanation

Suppose `vec{OP}` is inclined at angle `gamma` to `OZ`.

Let `l, m, n` be the direction cosines of `vec {OP}`. Then,

`l=cos 45^{circ}=frac{1}{sqrt{2}}`

`m=cos 60^{circ}=frac{1}{2}`

`n=cos gamma`

Now,


`l^{2}+m^{2}+n^{2}=1 `

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