If it is known that there is a point P 3a, 4a on the terminal edge of angle a, where a 0, then sina

Subtract the required to -cosa

Then discuss the positive and negative of A.

Get the answer to the leakage is plus or minus three-fifths of the way to search for hunger.

Hope, thank you.

Hello, calculate the length of the hypotenuse of the banquet finger as a 2 + (3a) 2 = a root number 10

So sina = 3a a root number 10 = 3 10 root number 10 hope to be auspicious!

When a 0, p is in the first quadrant, and the Pythagorean theorem is obtained: op=5a, then: sin =4 Yunhuai5

cosα=3/5

tanα=4/3

When a 0 and p are in the third quadrant, the Pythagorean theorem is obtained: op=-5a then: sin =-4 5

cosα=-3/5

tanα=4/3

The distance from point p to origin is 5|a|

It is divided into two types of situations.

1) When a>0.

sina = 4 out of 5 manuscripts

cosa = 5 points of the hood of filial piety 3

tana = 4/3

2) When a

Solution: Because p(4a,-3a), stool a 0), so 4a0, -3a 0

So p is in the third nanomacro quadrant.

So. sina = 3 5, yuki brigade cosa = -4 5 so. sina + cosa = 3 5-4 5 = -1 5 pro, please, yours is my motivation, thank you.

Definition of trigonometric function using or mu-balance.

When a>0 p(-4a,3a),r=5a, then tana=-3 4 cosa=-4 5

sina=3/5

When a<0 p(-4a,3a) and r=-5a, then tana=-3 4 cosa=4 bridge5

sina=-3/5

2 According to the induction formula.

cos( shirt do 2 + a) -sin (- a)] cos(11 2 -a) + sin (9 2 + a)].

sina -sina) sina + cosa) sina (sina-cosa) will you make a mistake in the question.

It should be an angle a with a value ranging from 0 to 180 and sina >0 so the angle a is an acute angle then the beginning is in the first or third quadrant so cosa=3 5 so tana=4 3