Which sum or difference identity would you use to verify that sin (90° + q) = cos q? a. cos (a -b) = cos a cos b + sin a sin b b. sin (a +b) = sin a cos b + cos a sin b c. sin (a -b) = sin a cos b- cos a sin b d. cos (a +b) = cos a cos b - sin a sin b

  b.  sin (a +b) = sin a cos b + cos a sin b

Step-by-step explanation:

Since you're trying to prove a relation involving the sine of a sum, that is the identity you would use:

  sin (a +b) = sin a cos b + cos a sin b

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  sin(90° +q) = sin(90°)cos(q) +cos(90°)sin(q)

  = 1·cos(q) +0·sin(q)

  = cos(q)

b. t=-25h+3

step-by-step explanation:

3/4 ÷ 3/4

step-by-step explanation:

basically divide any proper fraction with itself to fit the criteria.

so if we are using 3/4, then:

3/4 ÷ 3/4 = 1

so 1 is the quotient.

and the numerators for both these fractions is 3.   and if we divide the numerators:

3 ÷ 3 = 1

we see that quotient is equal to our original quotient as well.