Math problems should have steps, math problems, there are no detailed steps

sina)^2+2sinacosa+(cosa)^2=1/25sin2a=-24/25

If 0 a 2, then 1 2 sin a+cos a root number 2, and sin a+cos a = 1 5 1 2, so, 2 a 3 4

Thus there are: 2a 3 2

So, cos2a = -7 25

tan2a=sin2a/cos2a=24/7。

From sin a+cos a=1 5 5 to get cos a=1 5-sin a, cos 2 a=1 25-2 5sin a+sin 2 a, then 1-sin 2a=1 25-2 5sin a+sin 2 a is sin 2 a-1 5sin a-12 25=0 i.e. (sina-4 5) (sina + 3 5) = 0, and 0 a, then sina = 4 5, cosa = -3 5, then tana = -4 3, then tan2 a = 2tana (1-tan 2a) = 24 7

sin a + cos a）^2=1+sin 2a1/25=1+sin 2a

sin 2a=-24/25

So a is in the second quadrant.

So sin a>cos a

In the same way, we find sin a -cos a=7 5

Further sin a = 4 5

cos a=-3/5

tan a=-4/3

tan 2a = with a formula is enough.

The terminal edge of the angle falls on the straight line x+y=0, that is, on the straight line y=-x, the slope of y=-x is -1, so tan =-1 is divided by cos up and down in the original formula, and (3sin +2cos) (5sin -cos) =(3tan +

Select A, note that set B is really included in set A

then we get: 2a-3 3 and 3a-7 11

Solution: 3 A 6

1. A10 = 2 * 2 to the fourth power = 32

a13=1+（7-1）（-2）=-11

2. an=[1-(-1) to the nth power] 2*[a1+(n 2-1)d]+a2*[n+(-1)n+1]*q to the (n2-1) power.

III. 1966

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In this way, you don't have to think about plus or minus signs.