For any two vectors ` vec aa n d vec b` , prove that `| vec a+ vec b|lt=| vec a|+| vec b|`

Explanation

Given,

`(∣​a+b∣)^​2=(∣​a∣)^​2+(∣​b∣)^​2+2∣​a∣∣​b∣cosθ`


`(∣a∣​)^2+(∣​b∣)^​2=(∣​a∣)^​2+(∣b∣)^​2+2∣​a∣​+∣​b∣`​


`∣​a∣∣​b∣​cosθ⩽2∣​a∣∣b∣​`

So,

`(∣a+b∣)^​2⩽(∣a∣∣​b∣​)^2`
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