Solve 89x^2-8x*2*5xcos(60^circ)

$$89 { x }^{ 2 } -8x \times 2 \times 5x \cos ( 60 ^ { \circ } )$$

Evaluate

$$49x^{2}$$

Solution Steps

Multiply x and x to get x^{2}.

$$89x^{2}-2\times 5\times 8x^{2}\cos(60)$$

Multiply 2 and 5 to get 10.

$$89x^{2}-10\times 8x^{2}\cos(60)$$

Multiply 10 and 8 to get 80.

$$89x^{2}-80x^{2}\cos(60)$$

Get the value of \cos(60) from trigonometric values table.

$$89x^{2}-80x^{2}\times \frac{1}{2}$$

Multiply 80 and \frac{1}{2} to get 40.

$$89x^{2}-40x^{2}$$

Combine 89x^{2} and -40x^{2} to get 49x^{2}.

$$49x^{2}$$