Saturday

April 19, 2014

April 19, 2014

Posted by **Anonymous** on Saturday, March 29, 2008 at 7:18pm.

a = (4, 1) b = (-1,4)

a = (7,8) b = (4, -7)

You have to find the angle too.

Can someone please do these?

- Math -
**Damon**, Saturday, March 29, 2008 at 9:22pm4*-1 + 1*4 = 0

cos angle = 0, so angle is 90 or -90 (240)

remember algebra 1

y = m x + b

the slope of a line perpendicular to that is -1/m

here we have a slope of 1/4

and the other slope is 4/-1

sure enough, perpendicular

7*4 + 8*-7

7*(4-8)= -28

|A|*|B|* cos angle = -28

sqrt(49+64)*sqrt(16+49)* cos angle = -28

10.6 * 8.06 *cos angle = -28

cos angle = -.328

angle = 109 deg

**Related Questions**

math - given that vectors(p+2q) and (5p-4q) are orthogonal,if vectors p and q ...

Calculus - For which following condition, will the dot product of two vectors be...

Math - Product Dot Vectors - How would you expand and simplify the following ...

calculus - Find two unit vectors that make an angle of 60° with v = ‹3, 4›. Give...

PHYSICS VECTORS - 1. The problem statement, all variables and given/known data ...

Calculus - Two force vectors act on an object and the dot product of the two ...

math - given that vectors(p+2q) and (5p-4q) are orthogonal,if vectors p and q ...

Calculus - Let u = (-2,3) and v = (5,-6). Find the sum and the dot product of ...

Calculus - Find the dot product of the pair of vectors; s=4i +j t=-i -j

Physics (vectors) - Given vectors A= (Axi + Ayj), B= (Byj+Bzk) and C= (Cyj + Czk...