Answer:
[tex]f(resultand) = \sqrt{ {f1}^{2} + {f2}^{2} + 2f1f2 \cos( \alpha ) } \\ 14 = \sqrt{ {7}^{2} + {10}^{2} + 2 \times 7 \times 10 \cos( \alpha ) } \\ {14}^{2} = 49 + 100 + 140 \cos( \alpha ) \\ 196 = 149 + 140 \cos( \alpha ) \\ 196 - 149 = 140 \cos( \alpha ) \\ 47 = 140 \cos( \alpha ) \\ \cos( \alpha ) = \frac{47}{140} = .99 \\ thank \: you[/tex]
