Answer the following:

Let a = ci + j and b = 8i + 8j. Find c so that a and b are orthogonal. C = i 5. 6. Find two unit vectors in 2-space that make an angle of 450 with 7i + 4j. Let a = ci + jandb = 9i + 12j. Find c so that the angle between a and b is . Round your answers to four decimal places and enter the values in increasing order. NOTE: Enter the exact answers in terms of i, j and k. u = i u =