Hi there. I was surprised by the following issue with

**DSolve[]**. I solve a simple boundary value problem:

**A v''(t)+B v(t) = F(t)**where

**A**,

**B** -- 3x3 constant matrices,

**v(t)** -- 3-component vector-function to be search,

**F(t)** -- given vector-function. Each component of

**v(t)** satisfies boundary conditions at the point 0 and 1. The problem is straightforward and it seems no issue of using DSolve should appear for any admissible

**F(t)**.

In my case

is calculated on previous steps. The right part comprises polynomials and hyperbolic sine/cosine.

A={{-0.0446976691736994485306570961892697746090666666666666666666674378662`49.52287874528033,-0.0122435407636821029041771104742790256341333333333333333333335631248`49.52287874528033,0},{-0.0122435407636821029041771104742790256341333333333333333333335631248`49.52287874528033,-0.0536598147341966552641382113292879430192666666666666666666675924962`49.52287874528033,-0.0096221112323151669431839721820219762858666666666666666666668472582`49.52287874528033},{0,-0.0096221112323151669431839721820219762858666666666666666666668472582`49.52287874528033,-0.0331417816735817254686794764933873221642666666666666666666672384845`49.52287874528033}};

B={{0.1340930075210983455919712885678093238272000000000000000000023813023`49.52287874528033,-0.0734612445820926174250626628456741538048000000000000000000013045678`49.52287874528033,0},{-0.0734612445820926174250626628456741538048000000000000000000013045678`49.52287874528033,0.1609794442025899657924146339878638290578000000000000000000028587673`49.52287874528033,-0.0577326673938910016591038330921318577152000000000000000000010252506`49.52287874528033},{0,-0.0577326673938910016591038330921318577152000000000000000000010252506`49.52287874528033,0.0994253450207451764060384294801619664928000000000000000000017656535`49.52287874528033}};

Cv={0.060631762939005728166908625722135170022399999999597036827`41.3422565562137*t,0.212780329640637665497499999999999999999999999999920322284`40.30310235657392-0.033216383531445125976959004348708196540349999999875698403`40.30279030542798*t+0.01606919809093710551519097865719197386425`39.93202436395856*Cosh[1.732050807568877293527446341505872366942805253810380628056`47.307206068870755*t]-0.037769720858996510599008062410418913996548100984997967758`40.303173934606086*Sinh[1.732050807568877293527446341505872366942805253810380628056`47.307206068870755*t],0.1114816941367198054600000000000000000000000000000000000000019797573`49.69897000433602};

(here

**Cv** used instead of

**F(t)** ). For solving the problem the following code is used:

Q = DSolve[{A[[1,1]] v1''[t]+A[[1,2]] v2''[t]+B[[1,1]] v1[t]+B[[1,2]] v2[t]==Cv[[1]], A[[2,1]] v1''[t]+A[[2,2]] v2''[t]+A[[2,3]] v3''[t]+B[[2,1]] v1[t]+B[[2,2]] v2[t]+B[[2,3]] v3[t]== Cv[[2]],

A[[3,2]] v2''[t]+A[[3,3]] v3''[t]+B[[3,2]] v2[t]+B[[3,3]] v3[t]== Cv[[3]], v1[0] == 0, v1[1] == 1, v2[0] == 0, v2[1] == 1, v3[0] == 0, v3[1] == 1}, {v1[t],v2[t],v3[t]}, t]

But calculation invokes the error

No more memory available.

Mathematica kernel has shut down.

Try quitting other applications and then retry.

or the error of kernel

I tried to transform the right part into exponential form

Cv0=TrigToExp[Cv]

Now

.

But DSolve cannot solve the problem at all:

Q = DSolve[{A[[1,1]] v1''[t]+A[[1,2]] v2''[t]+B[[1,1]] v1[t]+B[[1,2]] v2[t]== Cv[[1]], A[[2,1]] v1''[t]+A[[2,2]] v2''[t]+A[[2,3]] v3''[t]+B[[2,1]] v1[t]+B[[2,2]] v2[t]+B[[2,3]] v3[t]== Cv0[[2]],

A[[3,2]] v2''[t]+A[[3,3]] v3''[t]+B[[3,2]] v2[t]+B[[3,3]] v3[t]== Cv0[[3]], v1[0] == 0, v1[1] == 1, v2[0] == 0, v2[1] == 1, v3[0] == 0, v3[1] == 1}, {v1[t],v2[t],v3[t]}, t]

Result:

**Indeed, I don't understand, what goes wrong?**